Weather patterns on Earth may be

a

explanation:

many plants naturally reproduce this way, but it can also be induced artificially. horticulturalists have developed asexual propagation techniques that use vegetative plant parts to replicate plants. success rates and difficulty of propagation vary greatly. monocotyledons typically lack a vascular cambium and therefore are harder to propagate.

answer: substrate concentration. enzymes work best when there is a high enough substrate concentration for the reaction they catalyse.

looks like the answer is     c     to me!