If molecules can regulate gene expression, why might this be reason to be more concerned about the effects of pollution on the health of organisms?

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.

the answer to your question is tooth decay.