Norman grew skin in a lab by adding skin cells to a synthetic material. The skin functioned normally for 12 days. Then Norman separated some of the skin cells into cell membranes, cytoplasm, and vacuoles to study them. Which of the following were alive during Normans experiment?

A. The skin and the cytoplasm
B. The skin and the Skin cells
C. The cell membranes and skin cells
D. The cell membranes and cytoplasm