Red blood cells carry oxygen; white blood cells fight disease.
Ans.
Meiosis involves a type of cell division in sexually reproducing organisms that results in formation of four daughter cells from a single parent cell, having half of the genetic material as in parent cell. Meiosis is divided into meiosis I and meiosis II.
In gamete forming cells of humans are diploid cells and have 23 pairs of chromosomes (or 46 chromosomes). Each gamete forming mother cell undergoes meiotic division to form haploid daughter cells or gametes, each with 23 chromosomes.
Thus, the correct answer is 'twenty-three' as there are 23 chromosomes present in human sex cells at the end of meiosis II.
C) To gather info about the natural world, to explain natural phenomena, and allow reasonable predictions of future events
If the sperm cell fertilises the ovum, and implantation does not occur, then the corpus luteum degenerates and it turns into corpus albicans, stopping progesterone secretion. If fertilisation occurs and implantation also, the syncytiotrophoblast, the "root part" of the blastocyst (one of the early structures originated from the zygote), produces a hormone that is called <span>human chorionic gonadotropin (hCG). The hCG is what makes the corpus luteum keep secreting progesterone and maintain itself. The progesterone will then help keep the endometrium and, therefore, allow the development of the embryo to happen.</span>
