The

system contains glands that secrete hormones into the bloodstream, whereas the

system secretes substances through ducts.

The first blank is the endocrine system, I’m not sure about the second one.

Endocrine

Exocrine

Explanation:

Endocrine system contains glands that secrete hormones into the bloodstream, whereas the

Exocrine system secretes substances through ducts.

genetic variation can be caused by mutation (which can create entirely new alleles in a population), random mating, random fertilization, and recombination between homologous chromosomes during meiosis (which reshuffles alleles within an organism's offspring).