We hiked to the bottom of the grand canyon, while other friends hiked to the top of mt. everest. both of these activities occurred in the
troposphere
mesosphere
stratosphere
thermosphere

that is wrong, its not thymus.

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.