allerySurfactant in the alveoli
Aabsorbs CO₂ from blood directly
Btransports O₂ into capillaries
Cfilters dust particles from inhaled air
Dlowers surface tension so alveoli don't collapse
Answer & Solution
Correct answer: D. lowers surface tension so alveoli don't collapse
Surfactant is a lipid-protein mixture (mainly dipalmitoyl phosphatidylcholine) secreted by type II alveolar cells.
It lowers surface tension in the thin layer of water lining alveoli, preventing collapse during expiration.
Premature babies often lack it (respiratory distress syndrome).
Keep practising Unit 8G: Comparative Physiology: Circulation, Respiration & Gas Exchange
Browse all Unit 8G: Comparative Physiology: Circulation, Respiration & Gas Exchange questions for AP Biology, or explore more Biology topics.
Related questions
Fill the photosynthesis blanksMatch the organ to its functionDuring deficiency of oxygen in tissues of human beings, pyruvic acid is converted into lacChoose the correct path of urine in our bodyLack of oxygen in muscles often leads to cramps among cricketers. This results due toWhich is the first enzyme to mix with food in the digestive tract?The opening and closing of the stomatal pore depends uponChoose the event that does not occur in photosynthesis