Hi!
The correct option is B. Which genes are active.
Embryonic differentiation is a developmental process by which embryonic cells give rise to specialized cells and a diverse range of tissue structures. All of this unique cells essentially rise from a type of cells that are known as pluripotent cells.
But how do these pluripotent embryonic stem cells know which cells to differentiate into? This is where genes come into play. The cell has an inherent signalling ability that determines which gene is to be active and expressed. These specifically activated genes then translate into proteins for which it is specific, giving each cell, tissue and organ its particular identity.
Hope this helps!
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>
The correct answer choice is answer B.) The fossil record provides evidence of a common ancestor to many species. Hope this helped!
