An epidemic (or epiphytotic) is the development of disease: a. on a susceptible plant b. on a plant c. within a population of plants d. on a plant leafe. none of the others

The answer is B

Explanation:

An epidemic or epiphytotic is the development of plant disease that occur sporadically over and over and affects large numbers of susceptible plants.

both male and female gametes are produced by meiosis of the germ cells. therefore, both male and female gametes are haploid. one male and one female gamete unite during the fertilization to form the diploid zygote. in seed bearing plants, pollen grain is the male gametophyte, which produces sperm cells.