Question 16
EasyOriginal questionIn the lungs, oxygen passes into the blood through the walls of tiny air sacs called
Show the answer and explanation
CorrectNot quiteAnswer B
Correct answer: B
Explanation
The alveoli are millions of thin-walled sacs wrapped in blood capillaries.
Oxygen diffuses into the blood there and carbon dioxide diffuses out.
Worth noting
Villi are finger-like folds in the small intestine that absorb food; nephrons are in the kidneys.
- Concept
- Gas exchange in the alveoli
- Typical timeTypical
- 35 s
- Your timeYours
- —
Practise this chapter →
Ten questions from Biology, Human Body and Health, at your own pace.