Q: You are presented with the quiz "What happens to the density of a gas when heated?"   But you don't know the answer, so you turn to your teacher to ask for hints. He says that "if gas is heated then that gas will expand" and "if a material is heated, it expands and the density decreases".   So, what's the best answer to the question?

A: decreases


Q: You are presented with the quiz "What can reproduce with help from moving water, wind, or other organisms?"   But you don't know the answer, so you turn to your teacher to ask for hints. He says that "spores may be dispersed by moving water, wind, or other organisms" and "spores Fungi reproduce via spores".   So, what's the best answer to the question?

A: fungi


Q: You are presented with the quiz "Products that harm small animals can also protect what?"   But you don't know the answer, so you turn to your teacher to ask for hints. He says that "apesticide is used for protecting plants by killing insects" and "small animals are harmed by pesticides".   So, what's the best answer to the question?

A: plants


Q: You are presented with the quiz "what can cause blood pH to become unbalanced?"   But you don't know the answer, so you turn to your teacher to ask for hints. He says that "blood pH may become unbalanced if the rate of breathing is too fast or too slow" and "aerobic activities are exercises that cause deep breathing and a fast heart rate".   So, what's the best answer to the question?

A:
aerobic activities