What is the difference between adaptation and natural selection

Adaptation is both an evolutionary process and a product of natural selection: adaptation is a process of evolution in which traits are modified by natural selection; an adaptation is a phenotypic trait moulded by natural selection. In both cases the evolution is driven by natural selection.

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.