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>
Consumers. Obviously all animals are not b or c as there are animals that are both. Plants are producers as they produce energy, and animals consume the energy making them consumers.
Mitochondria, plastids and chloroplast all are surrounded by a double membrane
The answer is B, higher high tides. Because in the passage it states: "Because the tides seem to spring up."
