(4) organic catalysts
The job of catalysts in chemical reactions is to make the reaction go faster by lowering the amount of energy needed to activate the reaction. If less energy is needed for the reaction to occur, then the reaction can go faster because a large energy build-up is not needed.
I believe that the answer is D. If something has evolved, it can not interbreed with its old species. I think this is right!
Rate Brainliest user please!
C. testable and observable