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B. I. Observe both… (Class 10 Science SQP 2026-27, Q16B)

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ScienceCBSE Class 10 · Sample paper, session 2026-27 · 5 marks · Long answer

CBSE Class 10 Science sample paper 2026-27: question 16(B)

From the official CBSE sample question paper for 2026-27, section A, question 16(B), for 5 marks. Try it first; the hints and our step-by-step solution are below.

Q16(B) · 5 marks · Long answerCompetency-basedLife Processes

B. I. Observe both the diagrams A and B. Which diagram indicates inhalation? Describe how it occurs. II. If diffusion were to move oxygen in our body, it is estimated that it would take 3 years for a molecule of oxygen to get to our toes from our lungs. Then, how is oxygen delivered to all parts of our body?

  1. I

    Observe both the diagrams A and B. Which diagram indicates inhalation? Describe how it occurs.

    0 marks
  2. II

    If diffusion were to move oxygen in our body, it is estimated that it would take 3 years for a molecule of oxygen to get to our toes from our lungs. Then, how is oxygen delivered to all parts of our body?

    0 marks

Figure in the paper: Two diagrams of the human thorax labelled A and B, showing the ribcage and diaphragm (labelled Diaphragm). Red arrows show direction of movement of ribs and diaphragm in each diagram. See it in the official paper.

Source: official sample paper from cbseacademic.nic.in (PDF). See it in the full Sample paper 2026-27.

Hints

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

Hint 1

During breathing in, which way do the ribs and diaphragm move?

Hint 2

A bigger chest cavity means lower pressure, so which way does air move?

Hint 3

Which pigment in blood carries oxygen, and which organ pushes the blood around?

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. Diagram A shows inhalation (ribs moving up and out, diaphragm moving down).

    1 mark

  2. During inhalation the ribs are lifted (moved upwards and outwards) by the rib muscles.

    ½ mark

  3. The diaphragm contracts and flattens.

    ½ mark

  4. As a result the chest cavity becomes larger and the pressure in the lungs falls.

    ½ mark

  5. Air is sucked into the lungs and fills the alveoli.

    ½ mark

  6. II. Diffusion alone is far too slow. Humans use the respiratory pigment haemoglobin, present in red blood corpuscles, which has a very high affinity for oxygen and picks it up in the lungs. The heart then pumps this oxygen-rich blood quickly through the blood vessels to all parts of the body, including the toes.

    2 marks

Answer: I. Diagram A (per the scheme): ribs lift, diaphragm flattens, chest cavity enlarges, air is sucked in; II. Haemoglobin in RBCs binds oxygen strongly, and the heart pumps this oxygenated blood to all body parts.

Where the marks are

  • Identifies A as inhalation (1 mark)
  • Ribs lifted (½ mark)
  • Diaphragm flattened (½ mark)
  • Chest cavity enlarges (½ mark)
  • Air sucked in (½ mark)
  • Haemoglobin in RBCs with high O₂ affinity, and the heart pumps oxygenated blood to the body (2 marks)

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 paperSample paper 2026-27: 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.