Skip to content

Answer the following. (Science 2025 31/2/1 Q29)

questionbuddy.in/q/cbse-10-science-2025-31-2-1-q29

ScienceCBSE Class 10 · Board exam 2025, set 31/2/1 · 3 marks · Short answer

CBSE Class 10 Science 2025: question 29

Set in the CBSE Class 10 board exam of 2025, paper 31/2/1, section C, question 29, for 3 marks. Try it first; the hints and our step-by-step solution are below.

Q29 · 3 marks · Short answerControl and Coordination

Answer the following.

  1. (a)

    Define hormone.

    0 marks
  2. (b)

    "Hormones should be secreted in precise quantities. We have a feedback mechanism through which this is done." With the help of an example justify the statement.

    0 marks

Source: official question paper from cbse.gov.in (PDF). See it in the full 2025 board paper, set 31/2/1.

Hints

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

Hint 1

Hormones are 'chemical messengers'. How do they reach their target?

Hint 2

Think about how the pancreas responds to blood sugar going up and going down.

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. (a) Hormones are chemical messengers secreted by endocrine glands in one part of the body. They travel through the blood to target organs or tissues and regulate body functions.

    1 mark

  2. (b) Example, insulin and blood sugar: when the blood sugar level rises (e.g. after a meal), cells of the pancreas detect it and secrete more insulin. Insulin lowers the blood sugar level.

    1 mark

  3. When the blood sugar level falls, the pancreas detects this and reduces insulin secretion. So the timing and amount of the hormone are controlled by a feedback mechanism, and the hormone is released in precise quantities.

    1 mark

Answer: (a) Chemical messengers carried by blood to target organs to regulate body functions. (b) Blood sugar–insulin feedback: high sugar → more insulin; low sugar → less insulin.

Where the marks are

  • Correct definition of hormone (1 mark)
  • Example of feedback control (e.g. rise in blood sugar → pancreas secretes more insulin, fall → less insulin) (2 marks)

Revise the chapter

Practise this chapterBoard-style questions from Control and Coordination, one at a time, marked against the answer key and marking points.Back to the full paper2025 board paper, set 31/2/1: 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.