Given a scientific question and its correct answer, generate supporting facts for the answer. This supporting fact can be an explanation for the answer to the given question.

Question: Where does the process of digestion start? Answer: mouth
Digestion starts in the mouth. When food is swallowed, it travels through the esophagus to the stomach. In the stomach, digestion continues and a small amount of absorption of nutrients takes place.

Question: What do people apply to their lawns that causes water pollution? Answer: chemicals
People pollute water when they apply excess chemicals to their lawn. They may also dispose of pollutants incorrectly.

Question: The cells of all protists have a what? Answer: nucleus
The cells of all protists have a nucleus. They also have other membrane-bound organelles. For example, all of them have mitochondria, and some of them have chloroplasts.