Learn

Saturday, 10 October

NEET UG 2021 · Zoology · Question 163

NEET 2021 Zoology, question 163

Question 163 of the NEET 2021 paper (code O1) is a Zoology question from Breathing and Exchange of Gases. Its idea, Partial Pressures of O2 and CO2, was asked only this once in NEET 2017–2026. The NTA final answer key gives option 3.

Updated 2026-10-08

Q163 · Zoology

The partial pressures (in mm Hg) of oxygen (O2\mathrm{O_2}) and carbon dioxide (CO2\mathrm{CO_2}) at alveoli (the site of diffusion) are :

  1. 1pO2\mathrm{pO_2} = 95 and pCO2\mathrm{pCO_2} = 40
  2. 2pO2\mathrm{pO_2} = 159 and pCO2\mathrm{pCO_2} = 0.3
  3. 3pO2\mathrm{pO_2} = 104 and pCO2\mathrm{pCO_2} = 40Official answer
  4. 4pO2\mathrm{pO_2} = 40 and pCO2\mathrm{pCO_2} = 45

Official answer: option 3 · NTA final answer key

Same idea

The only question on Partial Pressures of O2 and CO2

No other NEET paper from 2017–2026 tested this exact idea.

Partial Pressures of O2 and CO2: every question and how it was framed

The chapter

Breathing and Exchange of Gases in ten years of NEET

17 questions from 2017–2026, asked in 9 of 10 papers, about 1.6 a paper. Oxygen Dissociation Curve alone had 6.

Chapter analysisStudy this chapterPractise this chapter

Breathing and Exchange of Gases: questions per paper

0241’173’182’192’203’212’221’232’241’250’26