Question

Through which of the following body parts do humans take in the energy they need to survive?
A - mouth
B - intestines
C - skin
D - stomach

Answer 1

This looks simple but it is something of an ambiguous question.

Humans get energy from the energy stored in the chemical bonds in their food, so the obvious of the two possible answers is...?

Answer 2

I thought mouth but I'm not sure

Answer 3

Yes, the simple (and almost certainly correct) answer is the mouth.

But to a physiologist, the space inside the digestive tract technically is not 'inside' the body. It is like a passage way through the body as it opens at both ends (the mouth and anus) to the outside world.

In that context, food enters the body when it passes from the digestive tract to the actual tissues of the person. In that context, the correct answer is the intestine, as no absorption takes place inside the stomach.

Answer 4

Skin's primary function is to shield against outside elements.

You got Mouth, Stomach, and intestines to choose from:
1.) Mouth is the first part where the intake of food happens, as well as breaking down of food through chewing and mixture with the enzyme called saliva (Saliva also kills some harmful bacterias)
2.) Stomach is the second part of the food breakdown, but uses a powerful digestive enzyme called the Gastric acid, mostly for killing even more harmful germs that slipped past the saliva.
3.) After the stomach, the small intestines then gather the nutrients from the broken down food traveling through and distributes it to the rest of the body.