In the lock-and-key model of enzyme action, the fits into the of the enzyme. a. product; substrate. b. active site; product. c. substrate; active site. d. active site; substrate.

The answer is letter D. Substrate; Active Site The enzyme itself remains unchanged.  It advise the active place of an enzyme is frequently reshaped by interactions with the substrate until the substrate is completely bound and the chemical reaction occurs, the lock and key model.

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.