Hello! The answers are not A or C, because those are true. Embryonic stem cells do make up the cell mass of the blastocyst and undifferentiated cells can repair or replace bad cells. Adult stem cells are not multi potent and can not differentiate into different types of cells. The answer is D.
The answer to this question would be B. the use of stem cells is without any objections since it can be used in therapies to help humans. The use of stem cell has many controversies, mostly in the religious group that is pro-life. Since the cell of a zygote is totipotent and be able to differentiate into the most type of cell, it is better to use zygote cells. But some religions consider that cell is already human after fertilization, thus using zygote cells is considered as killing a human. Human blood cell and umbilical cord are multipotent. There should be no pluripotent in the adult by default, but there <span>is </span>some research about induced pluripotent stem cell (IPSCS) in the adult.
Hydrogen is used by plants which combine it with carbon during the photosynthesis process and release oxygen into the atmosphere which is used by all living beings.
