Problem:
Question 1: Define fertilization and explain why numerous spermatozoa are required to fertilize a secondary oocyte.
Question 2: Identify the stage of development that results from cleavage. What developmental stage begins once the zygote arrives in the uterine cavity?
Question 3: Describe the blastocyst and its role in implantation.
Question 4: Describe gastrulation and the formation of the germ layers.
Question 5: Name the four extra-embryonic membranes.
Question 6: Describe the placental hormones.
Could someone help to explain the answer of these questions.