All the cells in a person's body have the same DNA and the same genes. However, the difference between cells in different tissues and organs is that the "expression" of the genes differs between cells. Expression means that the message from the DNA is being copied and made into protein.
Isotopes are elements with same atomic number Z= number of protons but different mass number A, where A= Z+N, N= number of neutrons which is variable. As for radioisotopes, I’ve never heard of them before !
Structure A is the mitochondria
They catalyze the chemical reactions. For the molecules at the beginning for the cycle.
Answer:
cell membrane is the answer
