AP BIOLOGY

Detailed explanation-1: -At conception, an egg cell and a sperm cell combine to form a zygote (46 chromosomes or 23 pairs). This is the 1st cell of a new individual. The halving of the number of chromosomes in gametes ensures that zygotes have the same number of chromosomes from one generation to the next.

Detailed explanation-2: -The sperm and egg are haploid ( n); they carry half the number of chromosomes of the body cells (in humans, 23 in each sperm and egg). Meiosis thus makes it possible to maintain a constant number of chromosomes in a species that reproduces sexually by halving the number of chromosomes in the reproductive cells.

Detailed explanation-3: -Meiosis is important for three main reasons: it allows sexual reproduction of diploid organisms, it enables genetic diversity, and it aids the repair of genetic defects.

Detailed explanation-4: -The other type of cell division, meiosis, ensures that humans have the same number of chromosomes in each generation. It is a two-step process that reduces the chromosome number by half-from 46 to 23-to form sperm and egg cells.

Detailed explanation-5: -Crossing over during meiosis results in the recombination of genetic material.