Chemical Coordination and Integration: gland, hormone, disorder

Free questions

30 solved MCQs, answer marked and reasoning written out

Every question below is free to read — no sign-up, no email. 2 of them are real questions from past NEET papers. The other 196 questions in this chapter are in the book and in practice access.

1. Q1 Multi-statement analysis

   Regarding pituitary regulation: (i) the anterior pituitary is regulated by hypothalamic hormones via portal circulation (ii) the posterior pituitary is under direct neural regulation of the hypothalamus (iii) both lobes are thus regulated, directly or indirectly, by the hypothalamus (iv) the pituitary is attached to the hypothalamus by a stalk. How many are correct?

   1. 1.One
   2. 2.Two
   3. 3.Three
   4. 4.FourCorrect answer

   Why option 4 is the answer

   The trap: All four are correct.

   What this is testing: how the hypothalamus controls both pituitary lobes.

   All four statements are correct. The anterior pituitary is controlled by hypothalamic hormones carried through the portal circulation, while the posterior pituitary is under direct neural control - so both lobes answer to the hypothalamus, one chemically and one electrically, and the pituitary hangs from it by a stalk.

   No statement here is wrong; do not manufacture a trap where the book gives none.

   One hypothalamus, two routes: a blood portal to the front lobe, nerve fibres to the back. Knowing which route serves which lobe answers most questions on this gland.

   NCERT Class 11 Biology, page 241

2. Q2 Multi-statement analysis

   Regarding the anterior pituitary (pars distalis): (i) it produces growth hormone (ii) it produces prolactin, TSH and ACTH (iii) it produces oxytocin and vasopressin (iv) LH and FSH are produced by the posterior pituitary. How many are correct?

   1. 1.One
   2. 2.TwoCorrect answer
   3. 3.Three
   4. 4.Four

   Why option 2 is the answer

   The trap: (i) and (ii) correct; oxytocin and vasopressin are produced by the HYPOTHALAMUS, not the anterior pituitary, and LH/FSH are anterior, not posterior, pituitary hormones, so (iii) and (iv) are both wrong.

   What this is testing: which hormones the anterior pituitary actually makes.

   (i) and (ii) are correct - the anterior pituitary (pars distalis) makes growth hormone, plus prolactin, TSH and ACTH. (iii) and (iv) are both traps: oxytocin and vasopressin are made by the HYPOTHALAMUS, not the anterior pituitary, and LH/FSH are themselves ANTERIOR pituitary hormones, not posterior ones - the question scrambles both lobes at once.

   So two statements are correct.

   Six hormones from the anterior lobe, two made in the hypothalamus and merely stored in the posterior. A hormone moved between lobes is the planted error.

   NCERT Class 11 Biology, page 241

3. Q3 Multi-statement analysis

   Regarding prolactin, TSH and ACTH: (i) prolactin regulates growth of mammary glands and milk formation (ii) ACTH stimulates synthesis of mineralocorticoids from the adrenal medulla (iii) TSH stimulates synthesis and secretion of thyroid hormones (iv) ACTH stimulates glucocorticoid secretion from the adrenal medulla. How many are correct?

   1. 1.One
   2. 2.TwoCorrect answer
   3. 3.Three
   4. 4.Four

   Why option 2 is the answer

   The trap: (i) and (iii) correct; ACTH in fact stimulates GLUCOCORTICOIDS, and it acts on the adrenal CORTEX, not the medulla, so both (ii) and (iv) misattribute the target and hormone class.

   What this is testing: what ACTH actually targets and stimulates.

   (i) and (iii) are correct: prolactin governs mammary growth and milk formation, and TSH drives thyroid hormone synthesis. (ii) and (iv) are both traps - ACTH acts on the adrenal CORTEX, not the medulla, and it stimulates GLUCOCORTICOID secretion, not mineralocorticoids. Both errors move ACTH's target to the wrong zone and the wrong hormone class.

   So two statements are correct.

   ACTH is adrenoCORTICOtrophic: the name names its target. It feeds the cortex, and what the cortex answers with is the glucocorticoid.

   NCERT Class 11 Biology, page 242

4. Q4 Multi-statement analysis

   Regarding vasopressin (ADH): (i) it stimulates resorption of water and electrolytes by the distal tubules (ii) its impairment leads to excessive water retention (iii) it is also called anti-diuretic hormone (iv) it acts mainly on the liver rather than the kidney. How many are correct?

   1. 1.One
   2. 2.TwoCorrect answer
   3. 3.Three
   4. 4.Four

   Why option 2 is the answer

   The trap: (i) and (iii) correct; ADH impairment actually causes water LOSS and dehydration (diabetes insipidus), and ADH acts mainly on the KIDNEY, not the liver, so (ii) and (iv) are both wrong.

   What this is testing: what vasopressin (ADH) does and what happens when it fails.

   (i) and (iii) are correct: ADH stimulates water and electrolyte resorption at the distal tubules, and is also called anti-diuretic hormone. (ii) and (iv) are both traps - impaired ADH causes excessive water LOSS (diabetes insipidus), not retention, and ADH acts mainly on the KIDNEY, not the liver.

   So two statements are correct.

   Anti-diuretic means it stops urine. Remove it and urine pours out, which is diabetes insipidus - the opposite of retention.

   NCERT Class 11 Biology, page 243

5. Q5 Multi-statement analysis

   Regarding the pineal gland: (i) it is located on the dorsal side of the forebrain (ii) it secretes melatonin (iii) melatonin regulates the 24-hour diurnal rhythm of the body (iv) melatonin has no influence on pigmentation or metabolism. How many are correct?

   1. 1.One
   2. 2.Two
   3. 3.ThreeCorrect answer
   4. 4.Four

   Why option 3 is the answer

   The trap: (i)–(iii) correct; melatonin DOES influence metabolism, pigmentation, the menstrual cycle and defence capability, so (iv) is wrong.

   What this is testing: the range of what melatonin actually regulates.

   (i)-(iii) are correct: the pineal gland sits on the dorsal forebrain, secretes melatonin, and melatonin sets the body's 24-hour diurnal rhythm. (iv) is the trap - melatonin DOES influence pigmentation, metabolism, the menstrual cycle and immune defence; "no influence" denies functions the textbook explicitly gives it.

   So three statements are correct.

   Melatonin's list is long: the daily rhythm, pigmentation, metabolism, the menstrual cycle and the body's defences. 'No influence' is almost never true of it.

   NCERT Class 11 Biology, page 243

6. Q6 Multi-statement analysis

   Regarding hypothyroidism during pregnancy: (i) it causes defective development and maturation of the growing baby (ii) it always causes gigantism in the child (iii) it may cause mental retardation and low intelligence quotient (iv) it is unrelated to maternal iodine intake. How many are correct?

   1. 1.One
   2. 2.TwoCorrect answer
   3. 3.Three
   4. 4.Four

   Why option 2 is the answer

   The trap: (i) and (iii) correct; gigantism is caused by excess GROWTH HORMONE, not hypothyroidism, and hypothyroidism here is typically linked to maternal iodine DEFICIENCY, so (ii) and (iv) are both wrong.

   What this is testing: the consequences of maternal hypothyroidism for the child.

   (i) and (iii) are correct: hypothyroidism in pregnancy causes defective development of the baby and can cause mental retardation with a low IQ. (ii) and (iv) are both traps - the resulting condition is not gigantism, which comes from excess growth hormone, and it is closely tied to maternal iodine DEFICIENCY, not unrelated to it.

   So two statements are correct.

   Too little thyroid hormone in pregnancy holds the child's development back. Gigantism is a growth-hormone story from a different gland entirely.

   NCERT Class 11 Biology, page 243

7. Q7 Multi-statement analysis

   Regarding the parathyroid glands: (i) four parathyroid glands are present in humans (ii) their secretion is regulated by circulating sodium ion levels (iii) they secrete parathyroid hormone (PTH), a peptide hormone (iv) PTH is a hypocalcemic hormone. How many are correct?

   1. 1.One
   2. 2.TwoCorrect answer
   3. 3.Three
   4. 4.Four

   Why option 2 is the answer

   The trap: (i) and (iii) correct; PTH secretion is actually regulated by circulating CALCIUM ion levels, not sodium, and PTH is a HYPERcalcemic, not hypocalcemic, hormone, so (ii) and (iv) are both wrong.

   What this is testing: what regulates PTH secretion and its effect on blood calcium.

   (i) and (iii) are correct: four parathyroid glands are present in humans, and PTH is a peptide hormone. (ii) and (iv) are both traps - PTH secretion is regulated by circulating CALCIUM, not sodium, and PTH is a HYPERcalcemic hormone, raising blood calcium, not lowering it.

   So two statements are correct.

   PTH watches calcium and raises it. Sodium belongs to aldosterone, and lowering calcium belongs to calcitonin - three hormones, three jobs.

   NCERT Class 11 Biology, page 244

8. Q8 Multi-statement analysis

   Regarding catecholamines and metabolism: (i) they stimulate breakdown of glycogen, raising blood glucose (ii) they stimulate breakdown of lipids (iii) they stimulate breakdown of proteins (iv) they stimulate glycogen synthesis, lowering blood glucose. How many are correct?

   1. 1.One
   2. 2.Two
   3. 3.ThreeCorrect answer
   4. 4.Four

   Why option 3 is the answer

   The trap: (i)–(iii) correct; catecholamines promote glycogen BREAKDOWN (glycogenolysis), raising, not lowering, blood glucose, so (iv) is wrong.

   What this is testing: how catecholamines affect blood glucose.

   (i)-(iii) are correct: catecholamines break down glycogen to raise blood glucose, and also break down lipids and proteins for quick energy. (iv) is the trap and reverses (i) - catecholamines promote glycogen BREAKDOWN, not synthesis, so blood glucose rises rather than falls during an emergency.

   So three statements are correct.

   In an emergency the body spends, it does not save. Every catecholamine action releases fuel rather than storing it, so blood glucose can only rise.

   NCERT Class 11 Biology, page 245

9. Q9 Assertion and Reason

   AssertionThe adrenal cortex has three histologically distinct zones.

   ReasonThe outer zona glomerulosa, middle zona fasciculata and inner zona reticularis together secrete corticoids.

   1. 1.Both A and R are true and R is the correct explanation of A
   2. 2.Both A and R are true but R is not the correct explanation of ACorrect answer
   3. 3.A is true but R is false
   4. 4.A is false but R is true

   Why option 2 is the answer

   The trap: Both are true of the adrenal cortex; the naming of the three zones is a parallel structural fact and does not itself explain why there are three zones.

   What this is testing: whether naming the three cortex zones explains why there are three of them.

   Both statements are true - the adrenal cortex does have three histologically distinct zones (zona glomerulosa, fasciculata, reticularis), and together they secrete corticoids. But R only restates the zones and what they make; it does not explain why the cortex is organised into three zones.

   So both are true but R does not explain A.

   A reason that only names the parts the assertion already mentioned is restating it, and restating is not explaining.

   NCERT Class 11 Biology, page 246

10. Q10 Assertion and Reason

    AssertionCortisol is involved in maintaining cardiovascular and kidney function.

    ReasonCortisol is the main glucocorticoid secreted by the adrenal cortex.

    1. 1.Both A and R are true and R is the correct explanation of A
    2. 2.Both A and R are true but R is not the correct explanation of ACorrect answer
    3. 3.A is true but R is false
    4. 4.A is false but R is true

    Why option 2 is the answer

    The trap: Both are true of cortisol; its identity as the main glucocorticoid is a parallel fact and does not itself explain its cardiovascular role.

    What this is testing: whether being "the main glucocorticoid" explains cortisol's cardiovascular role.

    Both statements are true of cortisol. But identifying cortisol as the main glucocorticoid is a classification fact, not a mechanism - it does not by itself explain why cortisol helps maintain cardiovascular and kidney function.

    So both are true but R does not explain A.

    Naming what a hormone IS does not explain what it DOES. A classification fact can be perfectly true and still not be the mechanism.

    NCERT Class 11 Biology, page 246

11. Q11 Assertion and Reason

    AssertionEach hormone receptor is specific to one hormone only.

    ReasonHormone-receptor complex formation leads to biochemical changes in the target tissue.

    1. 1.Both A and R are true and R is the correct explanation of A
    2. 2.Both A and R are true but R is not the correct explanation of ACorrect answer
    3. 3.A is true but R is false
    4. 4.A is false but R is true

    Why option 2 is the answer

    The trap: Both are true of hormone receptors; the downstream biochemical change is a parallel fact and does not explain receptor specificity.

    What this is testing: whether the downstream effect of a hormone-receptor complex explains why receptors are specific.

    Both statements are true - each hormone receptor is specific to just one hormone, and hormone-receptor binding does trigger biochemical change in the target tissue. But that second fact describes what happens after binding, not why the receptor recognises only one hormone.

    So both are true but R does not explain A.

    One statement is about which key fits the lock, the other about what happens once it turns. Both true, but the second does not explain the first.

    NCERT Class 11 Biology, page 248

12. Q12 Assertion and Reason

    AssertionPiloerection and increased alertness occur mainly during rest and digestion.

    ReasonAdrenaline and noradrenaline are secreted rapidly in response to stress and emergencies.

    1. 1.Both A and R are true and R is the correct explanation of A
    2. 2.Both A and R are true but R is not the correct explanation of A
    3. 3.A is true but R is false
    4. 4.A is false but R is trueCorrect answer

    Why option 4 is the answer

    The trap: A is false — piloerection and alertness occur during FIGHT-OR-FLIGHT, not rest and digestion; R correctly names the hormones and the conditions that trigger them.

    What this is testing: when catecholamine-driven effects like piloerection actually occur.

    The assertion is false - piloerection and alertness happen mainly during FIGHT-OR-FLIGHT, the stress response, not during rest and digestion, which is the calm, parasympathetic state. The reason is true: adrenaline and noradrenaline are released rapidly under stress, producing exactly those effects the assertion misplaces.

    So A is false but R is true.

    Hair standing up and eyes wide open are emergency signs, never rest signs. The reason here is true and quietly contradicts the assertion.

    NCERT Class 11 Biology, page 245

13. Q13 Assertion and Reason

    AssertionAldosterone lowers blood pressure.

    ReasonAldosterone stimulates reabsorption of Na+ and water at the renal tubules, expanding body fluid volume.

    1. 1.Both A and R are true and R is the correct explanation of A
    2. 2.Both A and R are true but R is not the correct explanation of A
    3. 3.A is true but R is false
    4. 4.A is false but R is trueCorrect answer

    Why option 4 is the answer

    The trap: A is false — aldosterone helps RAISE and maintain blood pressure; R correctly describes the fluid-retention mechanism responsible.

    What this is testing: aldosterone's real effect on blood pressure.

    The assertion is false - aldosterone RAISES, not lowers, blood pressure. The reason is true, and it actually explains the opposite of what the assertion claims: by retaining sodium and water at the renal tubules, aldosterone expands fluid volume and raises, rather than lowers, blood pressure.

    So A is false but R is true.

    Watch for a reason that explains the OPPOSITE of its assertion. That mismatch is the surest sign the assertion has been reversed.

    NCERT Class 11 Biology, page 246

14. Q14 Assertion and Reason

    AssertionAddison's disease is marked by excessive energy and hyperactivity.

    ReasonUnderproduction of adrenal cortex hormones alters carbohydrate metabolism.

    1. 1.Both A and R are true and R is the correct explanation of A
    2. 2.Both A and R are true but R is not the correct explanation of A
    3. 3.A is true but R is false
    4. 4.A is false but R is trueCorrect answer

    Why option 4 is the answer

    The trap: A is false — Addison's disease causes acute WEAKNESS and fatigue, not hyperactivity; R correctly describes the underlying metabolic disturbance.

    What this is testing: the actual symptoms of Addison's disease.

    The assertion is false - Addison's disease causes acute WEAKNESS and fatigue, not excessive energy or hyperactivity. The reason is true: underproduction of adrenal cortex hormones does disturb carbohydrate metabolism, which is part of why the patient feels so weak.

    So A is false but R is true.

    Addison's disease drains a patient rather than energising them. Reversing the symptom is the standard trap on this disease.

    NCERT Class 11 Biology, page 245

15. Q15 Assertion and Reason

    AssertionCholecystokinin (CCK) acts on both the liver and the kidney.

    ReasonCCK stimulates secretion of pancreatic enzymes and bile juice respectively.

    1. 1.Both A and R are true and R is the correct explanation of A
    2. 2.Both A and R are true but R is not the correct explanation of A
    3. 3.A is true but R is false
    4. 4.A is false but R is trueCorrect answer

    Why option 4 is the answer

    The trap: A is false — CCK's targets are the PANCREAS and GALL BLADDER, not the liver and kidney; R correctly describes CCK's real secretory effects.

    What this is testing: CCK's real targets, pancreas and gall bladder, not liver and kidney.

    The assertion is false - CCK acts on the PANCREAS and GALL BLADDER, not the liver and kidney. The reason is true and correctly names CCK's actual effects: stimulating pancreatic enzyme secretion and bile release, at the pancreas and gall bladder respectively, not where A places them.

    So A is false but R is true.

    CCK targets the pancreas and the gall bladder. The actions listed are right; it is the pair of organs that has been moved.

    NCERT Class 11 Biology, page 248

16. Q16 Assertion and Reason

    AssertionDiabetes mellitus is associated with the appearance of ketone bodies.

    ReasonProlonged hyperglycemia in diabetes mellitus is associated with loss of glucose through urine.

    1. 1.Both A and R are true and R is the correct explanation of A
    2. 2.Both A and R are true but R is not the correct explanation of ACorrect answer
    3. 3.A is true but R is false
    4. 4.A is false but R is true

    Why option 2 is the answer

    The trap: Both are true consequences of diabetes mellitus running in parallel; the glycosuria does not itself explain ketone body formation.

    What this is testing: whether glycosuria explains ketone body formation in diabetes.

    Both statements are true consequences of diabetes mellitus - ketone bodies do appear, and prolonged hyperglycemia does cause glucose loss in urine. But glucose spilling into urine is a separate consequence from fat breakdown producing ketone bodies; one does not cause the other.

    So both are true but R does not explain A.

    Both are consequences of the same disease, arriving by different routes: glucose leaves in the urine, while fat breakdown throws off ketone bodies. Sharing a cause is not the same as one causing the other.

    NCERT Class 11 Biology, page 247

17. Q17 Assertion and Reason

    AssertionExcess growth hormone secretion in adults causes a significant further increase in height.

    ReasonLong bones have already stopped growing in adults, so the epiphyseal plates cannot elongate further.

    1. 1.Both A and R are true and R is the correct explanation of A
    2. 2.Both A and R are true but R is not the correct explanation of A
    3. 3.A is true but R is false
    4. 4.A is false but R is trueCorrect answer

    Why option 4 is the answer

    The trap: A is false — height does NOT increase in adults with excess GH, since R correctly explains why the epiphyseal plates cannot respond.

    What this is testing: why excess growth hormone in adults does not increase height.

    The assertion is false - excess GH in adults does NOT significantly increase height. The reason is true and explains exactly why: the long bones' epiphyseal plates have already closed, so they cannot elongate further, and the excess GH instead causes acromegaly.

    So A is false but R is true.

    Once the epiphyseal plates close, no amount of growth hormone adds height. That closure is the whole difference between gigantism and acromegaly.

    NCERT Class 11 Biology, page 242

18. Q18 Statement I and Statement II

    Statement IThe anterior pituitary secretes six hormones, including GH, PRL and TSH.

    Statement IIThe posterior pituitary synthesises oxytocin and vasopressin.

    1. 1.Both Statement I and Statement II are correct
    2. 2.Both Statement I and Statement II are incorrect
    3. 3.Statement I is correct but Statement II is incorrectCorrect answer
    4. 4.Statement I is incorrect but Statement II is correct

    Why option 3 is the answer

    The trap: I is correct; oxytocin and vasopressin are synthesised in the HYPOTHALAMUS, only stored/released by the posterior pituitary, so II is incorrect.

    What this is testing: whether the posterior pituitary synthesises oxytocin and vasopressin, or merely stores them.

    Statement I is correct: the anterior pituitary secretes six hormones including GH, prolactin and TSH. Statement II is the trap - oxytocin and vasopressin are SYNTHESISED in the hypothalamus; the posterior pituitary only stores and releases them.

    So Statement I is correct but Statement II is incorrect.

    Made in the hypothalamus, stored in the posterior pituitary. Substituting 'synthesises' for 'stores' is the standard trap on this pair of hormones.

    NCERT Class 11 Biology, page 241

19. Q19 Statement I and Statement II

    Statement IAldosterone stimulates reabsorption of Na+ and water at the renal tubules.

    Statement IIAldosterone stimulates reabsorption of K+ and phosphate ions.

    1. 1.Both Statement I and Statement II are correct
    2. 2.Both Statement I and Statement II are incorrect
    3. 3.Statement I is correct but Statement II is incorrectCorrect answer
    4. 4.Statement I is incorrect but Statement II is correct

    Why option 3 is the answer

    The trap: I is correct; aldosterone stimulates EXCRETION, not reabsorption, of K+ and phosphate, so II is incorrect.

    What this is testing: aldosterone's opposite effects on sodium versus potassium and phosphate.

    Statement I is correct: aldosterone stimulates reabsorption of Na+ and water at the renal tubules. Statement II is the trap - aldosterone stimulates EXCRETION, not reabsorption, of K+ and phosphate ions; it pulls sodium in while pushing potassium out.

    So Statement I is correct but Statement II is incorrect.

    Sodium in, potassium out. Aldosterone always trades one for the other, so any option that has it reabsorbing both is wrong on its face.

    NCERT Class 11 Biology, page 246

20. Q20 Statement I and Statement II

    Statement IErythropoietin is secreted by the juxtaglomerular cells of the kidney.

    Statement IIAtrial natriuretic factor is secreted by the atrial wall of the heart.

    1. 1.Both Statement I and Statement II are correctCorrect answer
    2. 2.Both Statement I and Statement II are incorrect
    3. 3.Statement I is correct but Statement II is incorrect
    4. 4.Statement I is incorrect but Statement II is correct

    Why option 1 is the answer

    The trap: Both statements are correct.

    What this is testing: the tissue sources of two non-glandular hormones, erythropoietin and ANF.

    Statement I is correct: erythropoietin is secreted by the juxtaglomerular cells of the kidney. Statement II is also correct: atrial natriuretic factor is secreted by the atrial wall of the heart.

    So both statements are correct.

    Neither the kidney nor the heart is an endocrine gland, and both secrete hormones regardless. That is the whole point of this pair.

    NCERT Class 11 Biology, page 248

21. Q21 Match the columns

    Match the androgen action with its target:

    Column I	Column II
    (a) Spermatogenesis	(iii) protein and carbohydrate metabolism
    (b) Accessory sex organs	(i) seminiferous tubules
    (c) Male sexual behaviour	(ii) epididymis, vas deferens, prostate
    (d) Anabolic effect	(iv) central neural system

    1. 1.(a)-(ii), (b)-(i), (c)-(iv), (d)-(iii)
    2. 2.(a)-(i), (b)-(ii), (c)-(iv), (d)-(iii)Correct answer
    3. 3.(a)-(i), (b)-(iv), (c)-(ii), (d)-(iii)
    4. 4.(a)-(iii), (b)-(ii), (c)-(iv), (d)-(i)

    Why option 2 is the answer

    The trap: Spermatogenesis-seminiferous tubules, accessory organs-epididymis/vas deferens/prostate, behaviour-CNS, anabolic effect-metabolism.

    What this is testing: matching each androgen action to its target tissue.

    Option 2 is correct: spermatogenesis happens in the seminiferous tubules, accessory sex organs are the epididymis, vas deferens and prostate, male sexual behaviour is a central-nervous-system effect, and the anabolic effect acts on protein and carbohydrate metabolism. Option 1 wrongly swaps the spermatogenesis and accessory-organ targets against each other.

    So option 2 is correct.

    Androgens work in four places at once: the seminiferous tubules, the accessory sex organs, the brain, and the body's protein and carbohydrate metabolism.

    NCERT Class 11 Biology, page 247

22. Q22 Match the columns

    Match the female reproductive hormone with its action:

    Column I	Column II
    (a) Estrogen	(ii) supports pregnancy
    (b) Progesterone	(iii) female secondary sex characters
    (c) Both estrogen and progesterone	(i) secreted by the testis
    (d) Neither	(iv) act on mammary glands

    1. 1.(a)-(iii), (b)-(ii), (c)-(iv), (d)-(i)Correct answer
    2. 2.(a)-(ii), (b)-(iii), (c)-(iv), (d)-(i)
    3. 3.(a)-(iii), (b)-(iv), (c)-(ii), (d)-(i)
    4. 4.(a)-(i), (b)-(ii), (c)-(iv), (d)-(iii)

    Why option 1 is the answer

    The trap: Estrogen-secondary sex characters, progesterone-pregnancy, both-mammary gland action, neither-testis secretion.

    What this is testing: matching estrogen and progesterone to their actions, singly and together.

    Option 1 is correct: estrogen gives female secondary sex characters, progesterone supports pregnancy, both act on the mammary glands together, and neither is secreted by the testis. Option 2 wrongly swaps the estrogen and progesterone actions against each other.

    So option 1 is correct.

    Estrogen builds the body, progesterone maintains the pregnancy. Both meet at the mammary gland, and neither comes from the testis.

    NCERT Class 11 Biology, page 247

23. Q23 Match the columns

    Match the hormone with the metabolic process it stimulates:

    Column I	Column II
    (a) Glucagon	(ii) gluconeogenesis, lipolysis, proteolysis
    (b) Insulin	(iv) glycogenolysis, lipolysis, proteolysis
    (c) Cortisol	(i) glycogenesis
    (d) Catecholamines	(iii) glycogenolysis and gluconeogenesis

    1. 1.(a)-(i), (b)-(iii), (c)-(ii), (d)-(iv)
    2. 2.(a)-(iii), (b)-(ii), (c)-(i), (d)-(iv)
    3. 3.(a)-(iv), (b)-(i), (c)-(ii), (d)-(iii)
    4. 4.(a)-(iii), (b)-(i), (c)-(ii), (d)-(iv)Correct answer

    Why option 4 is the answer

    The trap: Glucagon-glycogenolysis/gluconeogenesis, insulin-glycogenesis, cortisol-gluconeogenesis/lipolysis/proteolysis, catecholamines-similar breakdown.

    What this is testing: matching four metabolic hormones to the processes they stimulate.

    Option 4 is correct: glucagon drives glycogenolysis and gluconeogenesis, insulin drives glycogenesis, cortisol drives gluconeogenesis with lipolysis and proteolysis, and catecholamines drive glycogenolysis with lipolysis and proteolysis. Option 1 wrongly swaps the glucagon and insulin effects against each other, reversing which one builds glycogen and which breaks it down.

    So option 4 is correct.

    Only insulin stores. Glucagon, cortisol and the catecholamines all break things down, which makes insulin the odd one out in any list like this.

    NCERT Class 11 Biology, page 246

24. Q24 Match the columns

    Match the endocrine structure with the number of its named parts:

    Column I	Column II
    (a) Pituitary gland	(iii) two parts: pars distalis, pars intermedia
    (b) Adenohypophysis	(iv) three zones
    (c) Adrenal cortex	(ii) two main cell types
    (d) Islets of Langerhans	(i) two lobes: adenohypophysis, neurohypophysis

    1. 1.(a)-(iii), (b)-(i), (c)-(iv), (d)-(ii)
    2. 2.(a)-(i), (b)-(iv), (c)-(iii), (d)-(ii)
    3. 3.(a)-(ii), (b)-(iii), (c)-(iv), (d)-(i)
    4. 4.(a)-(i), (b)-(iii), (c)-(iv), (d)-(ii)Correct answer

    Why option 4 is the answer

    The trap: Pituitary-two lobes, adenohypophysis-two parts, adrenal cortex-three zones, islets-two cell types.

    What this is testing: matching four endocrine structures to how many named parts each has.

    Option 4 is correct: the pituitary has two lobes (adenohypophysis, neurohypophysis), the adenohypophysis has two parts (pars distalis, pars intermedia), the adrenal cortex has three zones, and the Islets of Langerhans have two main cell types. Option 1 wrongly swaps the pituitary and adenohypophysis rows against each other.

    So option 4 is correct.

    Two, two, three, two. A counting question rewards one careful pass through the anatomy rather than any rule.

    NCERT Class 11 Biology, page 241

25. Q25 Exception / incorrect

    All of the following are true of iodine and the thyroid EXCEPT:

    1. 1.Iodine is essential for normal thyroid hormone synthesis
    2. 2.Iodine deficiency causes hypothyroidism
    3. 3.Iodine deficiency causes hyperthyroidismCorrect answer
    4. 4.Iodine deficiency can cause goitre

    Why option 3 is the answer

    The trap: Iodine deficiency causes HYPOthyroidism, not hyperthyroidism.

    What this is testing: whether iodine deficiency causes hypo- or hyperthyroidism.

    Options 1, 2 and 4 are true: iodine is essential for thyroid hormone synthesis, its deficiency causes hypothyroidism, and it can cause goitre. Option 3 is the exception - iodine deficiency causes HYPOthyroidism, not hyperthyroidism, since without iodine the gland cannot make enough hormone at all.

    So option 3 is the exception.

    A deficiency can only point downward. Hypo- goes with too little of anything, and the thyroid is no exception to that.

    NCERT Class 11 Biology, page 243

26. Q26 Exception / incorrect

    All of the following are true of the adrenal cortex zones EXCEPT:

    1. 1.Zona glomerulosa is the outer layer
    2. 2.Zona fasciculata is the middle layer
    3. 3.Zona reticularis is the inner layer
    4. 4.Zona reticularis is the outer layerCorrect answer

    Why option 4 is the answer

    The trap: The OUTER layer is the zona glomerulosa, not the zona reticularis.

    What this is testing: the correct outer-to-inner order of the adrenal cortex zones.

    Options 1, 2 and 3 are true: zona glomerulosa is outer, zona fasciculata is middle, and zona reticularis is inner. Option 4 is the exception and directly contradicts option 3 - the zona reticularis is the INNER layer, not the outer one.

    So option 4 is the exception.

    G, F, R from the outside in. Here option 4 flatly contradicts option 3, and when two options in one list cannot both be true, one of them is your answer.

    NCERT Class 11 Biology, page 246

27. Q27 Sequence / ordering

    Arrange the route of a hypothalamic releasing hormone correctly:

    1. 1.Anterior pituitary → portal circulation → axon → hypothalamic neuron
    2. 2.Hypothalamic neuron → axon → nerve ending → portal circulation → anterior pituitaryCorrect answer
    3. 3.Nerve ending → hypothalamic neuron → axon → anterior pituitary → portal circulation
    4. 4.Portal circulation → anterior pituitary → hypothalamic neuron → axon → nerve ending

    Why option 2 is the answer

    The trap: The hormone originates in the hypothalamic neuron, travels down the axon to a nerve ending, then reaches the anterior pituitary via the portal circulation.

    What this is testing: the correct route a hypothalamic releasing hormone travels to reach the anterior pituitary.

    Option 2 is correct: the hormone originates in the hypothalamic neuron, travels down the axon to a nerve ending, and reaches the anterior pituitary through the portal circulation. The other options reverse this sequence, starting from the anterior pituitary or portal circulation as if the signal ran backward, which it does not.

    So option 2 is correct.

    Neuron, axon, nerve ending, portal blood, pituitary. In a sequence question the source comes first and the target last.

    NCERT Class 11 Biology, page 241

28. Q28 Sequence / ordering

    Arrange the layers of the adrenal cortex from outermost to innermost:

    1. 1.Zona reticularis → zona fasciculata → zona glomerulosa
    2. 2.Zona fasciculata → zona glomerulosa → zona reticularis
    3. 3.Zona glomerulosa → zona fasciculata → zona reticularisCorrect answer
    4. 4.Zona reticularis → zona glomerulosa → zona fasciculata

    Why option 3 is the answer

    The trap: From outside inward: zona glomerulosa, zona fasciculata, then zona reticularis.

    What this is testing: the outer-to-inner order of the three adrenal cortex zones.

    Option 3 is correct: from outside inward, the order runs zona glomerulosa, then zona fasciculata, then zona reticularis. Other options place the zona reticularis first or the zona glomerulosa in the middle, reversing or scrambling the true outer-to-inner sequence.

    So option 3 is correct.

    Glomerulosa, fasciculata, reticularis - outermost to innermost, and in that same order every time it is asked.

    NCERT Class 11 Biology, page 246

29. Q29 NEET 2023

    Which of the following are NOT under the control of thyroid hormone? (A) maintenance of water and electrolyte balance (B) regulation of basal metabolic rate (C) normal rhythm of the sleep-wake cycle (D) development of the immune system (E) support of RBC formation. Which combination is correct?

    1. 1.D and E only
    2. 2.A and D only
    3. 3.B and C only
    4. 4.C and D onlyCorrect answer

    Why option 4 is the answer

    The trap: C and D are not thyroid-controlled: the sleep-wake cycle is governed by melatonin, and immune system development is governed by thymosins.

    What this is testing: which listed functions belong to thyroid hormone and which are wrongly attributed to it.

    C and D are not under thyroid control: the sleep-wake rhythm is set by melatonin from the pineal gland, and immune system development is driven by thymosins from the thymus, so option 4 is correct.

    A and B are genuine thyroid functions - water and electrolyte balance and basal metabolic rate are both thyroid-regulated. E, support of RBC formation, is also real, not an exception.

    The trap borrows two unrelated glands' jobs and pastes them onto the thyroid's long function list.

    NCERT Class 11 Biology, page 244

30. Q30 NEET 2021

    With regard to insulin, choose the correct options: (a) C-peptide is not present in mature insulin (b) the insulin produced by rDNA technology has C-peptide (c) proinsulin has C-peptide (d) the A-peptide and B-peptide of insulin are interconnected by disulphide bridges. Which combination is correct?

    1. 1.(b) and (d) only
    2. 2.(b) and (c) only
    3. 3.(a), (c) and (d) onlyCorrect answer
    4. 4.(a) and (d) only

    Why option 3 is the answer

    The trap: (a), (c) and (d) are correct; (b) is wrong since rDNA-produced (mature) insulin lacks the C-peptide, which is present only in proinsulin.

    What this is testing: the structure of insulin and proinsulin, and what rDNA insulin lacks.

    (a) is correct: mature insulin does not carry the C-peptide. (c) is correct: proinsulin, the precursor, does carry the C-peptide linking its A and B chains. (d) is correct: the A and B chains are held together by disulphide bridges.

    (b) is the trap - genetically engineered insulin is made to match the mature hormone, so it lacks the C-peptide too; only proinsulin carries it.

    So (a), (c) and (d) match option 3, while (b) wrongly gives manufactured insulin a feature that belongs only to its precursor.

    C-peptide is the join, discarded when proinsulin matures. Its absence is how a laboratory tells injected insulin from the body's own.

    NCERT Class 11 Biology, page 246