O Level / IGCSE Biology chapter 8: Human nutrition MCQs with answers
By Team Megalecture · Updated 4 Nov 2026
34 exam-style questions on Human nutrition, each with the answer and a short explanation. Ten of them are below to try. The chapter test draws ten fresh questions each time and is marked the moment you finish, with your score by topic.
Try each one, then open the answer. These ten stay the same; the test draws new ones every time.
1. In which region of the gut are most digested nutrients absorbed?
A
the stomach
B
the small intestine
C
the large intestine
D
the oesophagus
Show answer
Answer: B. Most digested nutrients are absorbed in the small intestine, where the ileum is folded into villi to give a large surface area.
2. Why must most food be digested before it can be absorbed?
A
to release energy from the food while it is still inside the gut cavity
B
so that the bacteria living in the gut can no longer use the food themselves
C
to make the food molecules larger so that they can be stored in the liver
D
large insoluble molecules must be broken into small soluble ones to be absorbed
Show answer
Answer: D. Large insoluble food molecules cannot pass through the gut wall. Digestion breaks them into small soluble molecules that can be absorbed into the blood.
3. Apart from food, how does the body obtain vitamin D?
A
it is absorbed from the air by the lungs when we breathe in
B
it is taken in from drinking water in the form of a mineral
C
it is made in the skin when the skin is exposed to strong sunlight
D
it is made in the liver from the protein in the diet
Show answer
Answer: C. The skin makes vitamin D when exposed to sunlight, as well as some being obtained from foods such as oily fish and eggs.
4. What is the importance of dietary fibre?
A
it adds bulk to the food, which helps to prevent constipation
B
it is used to build and repair muscle tissue
C
it carries oxygen in the blood to the respiring cells
D
it is the main source of energy for the cells of the body
Show answer
Answer: A. Dietary fibre adds bulk so that food moves along the gut by peristalsis, which helps to prevent constipation.
5. What is the function of hydrochloric acid in the stomach?
A
it neutralises the bile that enters from the liver
B
it digests the protein in the food into amino acids
C
it kills bacteria that are swallowed with food
D
it emulsifies fats into small droplets
Show answer
Answer: C. Hydrochloric acid kills most bacteria that enter with food and gives the acidic pH in which pepsin works best. The acid does not digest protein by itself, and bile emulsifies fats.
6. Which is an example of physical digestion?
A
amylase breaking down starch
B
protease breaking down protein
C
chewing food with the teeth
D
lipase breaking down fats
Show answer
Answer: C. Physical digestion breaks food into smaller pieces without changing the molecules. Enzyme action is chemical digestion.
7. In which region of the gut does physical digestion by muscular churning and chemical digestion of protein both happen in acidic conditions?
A
mouth
B
stomach
C
duodenum
D
colon
Show answer
Answer: B. The muscular stomach wall churns food, and pepsin digests protein in the acid. The mouth digests starch, not protein.
8. What is peristalsis?
A
waves of muscle contraction that push food along the gut
B
the chewing of food in the mouth to increase its surface area
C
the movement of digested food from the gut cavity into the blood
D
the churning of food in the stomach by its muscular walls to mix it with acid
Show answer
Answer: A. Peristalsis is the wave of contraction of circular and longitudinal muscles that pushes food along the gut. Churning and chewing are physical digestion, and absorption moves food into the blood.
9. Most of the water that is absorbed in the gut is absorbed in which region?
A
the oesophagus
B
the stomach
C
the small intestine
D
the rectum
Show answer
Answer: C. Water is absorbed from both the small intestine and the colon, but most of the water is absorbed in the small intestine. Very little is absorbed in the stomach.
10. How does bile help the digestion of fats?
A
it absorbs the digested fats from the duodenum into the lacteals
B
it emulsifies fat into droplets, giving a larger surface area for lipase
C
it stores fat in the liver until the lipase is ready to break it down
D
it breaks the fat molecules into fatty acids and glycerol, using lipase made in the liver
Show answer
Answer: B. Bile is made in the liver and does not contain enzymes. It emulsifies fats into small droplets, increasing the surface area so lipase can digest them faster.
34, each with the answer and a short explanation, across 3 topics: Diet, Human digestive system, Absorption and assimilation. Every chapter test draws ten of them, so you can take it many times.
Is the O Level / IGCSE Biology chapter 8 test free?
Yes. The test, the answers and the explanations are free and need no sign-up. Sign in only if you want your scores kept across devices.
How is the chapter test marked?
The moment you press Finish: your score, the right answer and an explanation for every question, and the ones you got wrong saved in My mistakes to retry.
