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Separation of right side and… (Class 10 Science 2026, Q12)

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ScienceCBSE Class 10 · Board exam 2026, set 31/3/1 · 2 marks · Very short answer

CBSE Class 10 Science 2026: question 12

Set in the CBSE Class 10 board exam of 2026, paper 31/3/1, section A, question 12, for 2 marks. Try it first; the hints and our step-by-step solution are below.

Q12 · 2 marks · Very short answerLife Processes

Separation of right side and left side of the heart is useful to keep oxygenated and deoxygenated blood from mixing. Various organisms have different types of heart.

  1. (I)

    Fill in the blanks (i) to (iii) correctly according to the type of organisms and their evolution in terms of blood circulation :

    OrganismsNumber of chambers in heartType of blood being circulatedType of circulation
    Fish(i) ______MixedSingle
    (ii) ______3-chamberedMixedIncomplete double circulation
    Birds and Mammals4-chamberedSeparated circulation path of oxygenated and deoxygenated blood(iii) ______
    0 marks
  2. (II)

    Which type of circulation is most efficient ?

    0 marks

Source: official question paper from cbse.gov.in (PDF). See it in the full 2026 board paper, set 31/3/1.

Hints

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

Hint 1

Fish have one atrium and one ventricle. Count the chambers.

Hint 2

Frogs and lizards have 3 chambers. A 4-chambered heart keeps the two kinds of blood fully separate, which affects how many times blood passes through the heart.

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)(i) Fish have a 2-chambered heart (one atrium and one ventricle).

    ½ mark

  2. (I)(ii) Amphibians / Reptiles have a 3-chambered heart with incomplete double circulation.

    ½ mark

  3. (I)(iii) In birds and mammals the circulation is double circulation: blood passes through the heart twice in each cycle.

    ½ mark

  4. (II) Double circulation (as in birds and mammals) is the most efficient. Oxygenated and deoxygenated blood never mix, so the body gets a highly efficient supply of oxygen.

    ½ mark

Answer: (I)(i) 2-chambered; (ii) Amphibians/Reptiles; (iii) Double circulation; (II) Double circulation

Where the marks are

  • 2-chambered heart for fish (½ mark)
  • Amphibians/Reptiles for the 3-chambered heart (½ mark)
  • Double circulation for birds and mammals (½ mark)
  • Double circulation named as the most efficient (½ mark)

Revise the chapter

  • Chapter: Life Processes (notes, formulas, where marks are lost and every past question)
Practise this chapterBoard-style questions from Life Processes, one at a time, marked against the answer key and marking points.Back to the full paper2026 board paper, set 31/3/1: 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.