the dried excrement of fish-eating sea birds, deposited in rocky coastal regions of South America: contains the urates, oxalates, and phosphates of ammonium and calcium; used as a fertilizer.
In prokaryotes there is only one rather simple type of cell division, which produces two identical daughter cells from one progenitor cell. This is asexual cell division, since it involves no sexual union of different individuals.
Sex Cell Production. Human sex cells are produced by a two-part cell division process called meiosis. Through a sequence of steps, the replicated genetic material in a parent cell is distributed among four daughter cells. Meiosis produces gametes with one-half the number of chromosomes as the parent cell. Because these cells have one-half the number of chromosomes as the parent cell, they are haploid cells. Human sex cells contain one complete set of 23 chromosomes. There are two stages of meiosis: meiosis I and meiosis II.