Enzymes act as catalysts because

a- they raise the activation energy

b- they lower the activation energy

c- they use activation energy

d- they maintain activation energy

•there must be variation for the particular trait within a population.

•the variation must be inheritable (that is, it must be capable of being passed on from the parents to their offspring).

•individuals with one version of the trait must produce more offspring than those with a different version of the trait.good

explanation:

oxygen +1 most likely