Which describes a single enzyme? A. Exists in many different shapes and sizes. B. Takes part in only one type of chemical reaction. C. Slows down the process of chemical digestion. D. Is involved in many types of chemical reactions.

How does the nervous system affect the excretory system?

Which statement is the best summary of the model? a-a series of aerobic and anaerobic reactions take place in cells b- the sun's energy moves through trophic levels in a food chain c-light energy is converted into stored chemical energy plants. d- food molecules are broken down in the cells if living things.

How many copies of genes do gametes have?