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Class 11 Biology — Chapter 14: Breathing and Exchange of Gases
60 practice questions · 20 Easy · 20 Medium · 20 Hard
Free NCERT-aligned multiple-choice practice for Class 11 Biology, Chapter 14 (Breathing and Exchange of Gases). Practise timed Easy, Medium and Hard quizzes with instant explanations — built for CBSE Board exams, JEE Main and NEET UG. Here are a few sample questions; sign in free to practise all 60.
Sample questions
Q1Easy
Site of gas exchange in lungs:
A.Alveoli✓ correct
B.Bronchi
C.Trachea
D.Larynx
Why
Thin-walled sacs surrounded by capillaries.
Q2Medium
Most O₂ in blood is carried by:
A.Haemoglobin✓ correct
B.Plasma dissolved
C.WBC
D.Platelets
Why
~97% bound to Hb as oxyhaemoglobin.
Q3Hard
Bohr effect: O₂ binding to Hb decreases when:
A.CO₂/H⁺ increases (lower pH)✓ correct
B.pH rises
C.Temperature falls
D.O₂ rises
Why
Releases O₂ in tissues with high CO₂.
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