Explain how enzyme works using the terms from 1-5

Enzymes are special proteins that increase the rate of a reaction by decreasing the amount of energy needed to get a reaction started.

the correct answer is:

a population changes in response to a change in the environment.

hydrogen is a compound or a single element and a element is a pure substence that cannot be separated into simpler subtances

clorine is a compound its a chemical substance that forms when two or more different elements combine

so both hydrogen and clorine are compounds