Love and Unity :) just kiddddding aging cells stop dividing because they become senescent. They do this by sending chemical signals to each other so that they know
I think it is A but not 100% sure. Think of an enzyme like a key unlock the lock is the protein. And to activate getting inside your car or house you have to fit the key into the lock.
Answer:
The flow of heat from Earth's interior to the surface is estimated at 47±2 terawatts (TW) and comes from two main sources in roughly equal amounts: the radiogenic heat produced by the radioactive decay of isotopes in the mantle and crust, and the primordial heat left over from the formation of Earth.
Answer: Endocytosis brings materials to the inside of the cell while exo takes them out. Exoocytosis has the vesicle being formed in the golgi apparatus which then fuses with the membrane, while endo has the vesicle. formed from the cell membrane which then gets into the cytoplasm.