Answer:
2 membrane layers cover up the nucleus
Oncogenes result from turning on, or activating proto oncogenes. Proto oncogenes are genes that code for positive cell cycle regulators, so proto oncogenes code for proteins that turn on cell division. Proto oncogenes are normal genes, but when they are mutated, they become oncogenes. Oncogenes are expressed too much, which makes them turn on cell division too much, which is cancer.
A. The hosts body could reject the transplanted stem cells
