I believe you're looking for "chemical digestion".
Chemical digestions is where food that we ate is digested into simpler and soluble molecules that can be absorbed by our body. Enzymes are used as a catalyst to speed up the reaction.
One example is the digestion of lipids. Enzyme named lipase is used to speed up the digestion of lipids into 3 fatty acid molecules and 1 glycerol. This way, our body can absorb these simple molecules, and use them in order to make our body function.
On the other hand, physical digestion does not include enzymes, such as chewing in our mouth, therefore, don't mix them up!
Answer:
It's C. They are mostly made up of hydrogen and helium
Easily can slip away from predators.
