The Occurrence of Human Identical Twins is Evidence That

Question

The occurrence of human identical twins is evidence that:
A) all human cells are totipotent.
B) no human totipotent cells have been identified.
C) the only totipotent human cell is the one-cell embryo.
D) cells in a two-cell human embryo are totipotent.
E) cells in a two-cell human embryo are pluripotent.

Accepted Answer

Cells in a two-cell human embryo are considered totipotent because they have the potential to develop into any cell type or even a complete organism, which is evidenced by the natural occurrence of identical twins from the splitting of an early embryo.