Question

Metabolism
The metabolism of food is important to the body. Food goes through a series of chemical reactions in the digestive system and new molecules are formed. The body must break down food because its molecules are complex. Energy is stored in the bonds holding these molecules together. When chemical reactions occur with oxygen, the bonds are broken, and the energy is released. The atoms before and after the reaction are the same, but the new molecules are less complex. The body uses many of the broken down parts to function.

The model shows the rearrangement of molecules when a boy eats some food.

As the boy eats food and takes in oxygen, oxygen becomes available for reaction and food becomes glucose. The molecules rearrange to water, protein, and energy.

Multiple Choice Question
Where does the matter that the boy uses for growth come from?

A.
Some of the matter comes from the oxygen he breathes, and his body creates the rest.

B.
Some of the matter comes from the food he eats, and his body creates the rest.

C.
All of the matter comes from the food he eats.

D.
All of the matter comes from the oxygen he breathes.

Answer 1

The correct answer is:

B. Some of the matter comes from the food he eats, and his body creates the rest.

This reflects that while some of the mass used for growth is derived from the nutrients in food, the body also synthesizes additional components as part of its metabolic processes.