Sex cells are formed in the testes and ovaries—parts of the reproductive
systems in men and women. Both testes and ovaries also produce
hormones, making them parts of what other system?
Question 4 options:

nervous

respiratory

excretory

endocrine

D. Endocrine system.

Explanation: The endocrine system is made of glands that produce hormones that regulate the human body's overall growth, metabolism, and sexual development and reproduction, as well as everyday things such as sleeping and emotions/mood.

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).