AP BIOLOGY

Detailed explanation-1: -Meiosis is where a diploid cell gives rise to haploid cells, and fertilization is where two haploid cells (gametes) fuse to form a diploid zygote.

Detailed explanation-2: -During fertilization, it is important that only two haploid cells fuse. A fusion of three or more cells, often referred to as re-fertilization, may lead to unwanted polyploidy, chromosome mis-segregation and production of defective or inviable progeny (Figure 1B).

Detailed explanation-3: -Solution : Secondary oocyte is formed by meiotic division of primary oocyte (2n). Therefore, it is haploid. Primary spermatocyte is formed by mitotic divison of spermatogonium (2n), therefore it is diploid.

Detailed explanation-4: -Fertilization is the process in which haploid gametes fuse to form a diploid cell called a zygote. To ensure that each zygote has the correct number of chromosomes, only one sperm can fuse with one egg.

Detailed explanation-5: -The zygote is endowed with genes from two parents, and thus it is diploid (carrying two sets of chromosomes). The joining of haploid gametes to produce a diploid zygote is a common feature in the sexual reproduction of all organisms except bacteria.