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(i) Arrange the following… (Class 12 Biology 2026, Q31b)

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BiologyCBSE Class 12 · Board exam 2026, set 57/5/1 · 5 marks · Long answer

CBSE Class 12 Biology 2026: question 31(b)

Set in the CBSE Class 12 board exam of 2026, paper 57/5/1, section E, question 31(b), for 5 marks. Try it first; the hints and our step-by-step solution are below.

Q31(b) · 5 marks · Long answerHuman Reproduction

(i) Arrange the following hormones in sequence of their secretion in a pregnant woman :
hCG; LH; FSH; Relaxin.
(ii) Mention the source and the functions of the above mentioned hormones. 1+4=5

Source: official question paper from cbse.gov.in (PDF). See it in the full 2026 board paper, set 57/5/1.

Hints

Open one hint at a time and try again before the next.

Hint 1

Follow the events in order: follicle growth, ovulation, maintenance of pregnancy, then birth.

Hint 2

Two of these hormones come from the pituitary. Of the other two, one comes from the placenta and one from the ovary late in pregnancy.

Step-by-step solution

Each step shows the marks it earns, as an examiner would award them. Checked by an independent re-solve from the question paper.

  1. (i) Sequence of secretion: FSH → LH → hCG → Relaxin.

    1 mark

  2. (ii) FSH – Source: anterior pituitary. Function: stimulates the growth and development of ovarian follicles during the follicular phase.

    1 mark

  3. LH – Source: anterior pituitary. Function: its mid-cycle surge causes rupture of the Graafian follicle and release of the ovum (ovulation). It also helps form the corpus luteum.

    1 mark

  4. hCG (human chorionic gonadotropin) – Source: placenta. Function: supports foetal growth, brings about metabolic changes in the mother and maintains pregnancy.

    1 mark

  5. Relaxin – Source: ovary, in the later phase of pregnancy. Function: facilitates parturition by relaxing the pelvic ligaments and softening the cervix.

    1 mark

Answer: (i) FSH, LH, hCG, Relaxin; (ii) FSH – anterior pituitary, follicle development; LH – anterior pituitary, ovulation; hCG – placenta, maintains pregnancy and supports foetal growth; Relaxin – ovary, facilitates parturition.

Where the marks are

  • Correct sequence FSH, LH, hCG, Relaxin (1 mark)
  • FSH: source (½ mark) and function (½ mark)
  • LH: source (½ mark) and function (½ mark)
  • hCG: source (½ mark) and function (½ mark)
  • Relaxin: source (½ mark) and function (½ mark)

Revise the chapter

  • Chapter: Human Reproduction (notes, formulas, where marks are lost and every past question)
Practise this chapterBoard-style questions from Human Reproduction, one at a time, marked against the answer key and marking points.Back to the full paper2026 board paper, set 57/5/1: every question, by section.

The question is transcribed from the official paper; figures are described in words. The solution, hints and chapter tag are ours. Spotted an error? Write tosupport@questionbuddy.in.