<span>4 molecules of oxygen. Haemoglobin is a protein found in the red blood cells, which carries oxygen to the cells to perform cellular respiration. Each red blood cell carries around 250 million haemoglobin. So the entire capacity of an RBC is around 1 billion oxygen molecules.</span>
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>
In Puerto Rico the earthquakes happen cause of that
