I Think this is the cell cycle. S phase is the synthesis phase. It is the replication of the DNA and splitting of the cytoplasm.
I hate the actions or behaviors that my have (or may not have) taken pace before someone dies?
Embryonic stem cells are pluripotent cells that are derived from the inner cell mass of a blastocyst before implantation. These cells have potential of treating a wide range of diseases and conditions, which is attributed to the fact that they have; self renewal property meaning that they can ploriferate indefinitely, the cells also have the special ability to differentiate into cells with specialized characteristics and functions. In addition the cells are unspecialized and therefore they can give rise to specialized cells.
I think the correct answer would be A. The yolk sac becomes the placenta. It is membranous sac that is attached to the embryo. It provides all the nutrition and the blood cells needed by the embryo. It is also called the umbilical vesicle.