Question

true or false

Most of the digestion of carbohydrates, proteins, and fats takes place in the stomach. *

Diarrhea is a common symptom of food-borne illnesses. *

All organisms have either lungs or gills that they use for gas exchange. *

Oxygen makes up about 20.9 % of the air that we breathe. *

When carbon dioxide diffuses into the bloodstream from body cells, it reacts with water molecules and forms carbonic acid, which lowers the pH of the blood. *

Answer 1

1. Most of the digestion of carbohydrates, proteins, and fats takes place in the stomach. FALSE.

This statement is false because most of the digestion takes place in the small intestine.

2. Diarrhea is a common symptom of food-borne illnesses. TRUE.

3. All organisms have either lungs or gills that they use for gas exchange. FALSE.

Some organisms, like frogs and flatworms, also have skin for gas exchange.

4. Oxygen makes up about 20.9 % of the air that we breathe. TRUE.

5. When carbon dioxide diffuses into the bloodstream from body cells, it reacts with water molecules and forms carbonic acid, which lowers the pH of the blood. TRUE.