a. A stem cell is an undifferentiated cell that when divided gives rise to another identical cell that replicates itself and another cell that can differentiate into many cell types.

b. Totipotent cells can form all the cell types in a body. Embryonic cells within the first couple of cell divisions after fertilization are the only cells that are totipotent.

c. Pluripotent cells can give rise to all of the cell types that make up the body; embryonic stem cells are considered pluripotent.

d. Multipotent cells can develop into more than one cell type, but are more limited than pluripotent cells; adult stem cells and cord blood stem cells are considered multipotent.

e. All of the above.

a. The endometrium has progenitor stem cells that can replace all of the endometrium during each menstrual cycle.

b. Multipotent endometrial cells can replace progenitor cells when depleted.

c. Recruitment of stem cells from outside of the uterus occurs in setting of increased demand such as ischemia or injury.

d. In the setting of overwhelming injury, especially in the setting of high estrogen levels, there may be insufficient stem cell recruitment to adequately repair the uterus resulting in conditions such as Asherman syndrome or other endometrial defects.

e. None of the above.