What technological advancement was necessary before scientists could begin to observe cells?

Which of the following describes what an activator an enhancer are

The krebs cycle is also known as the calvin cycle pyruvic acid cycle carbon - oxygen cycle citric acid cycle

Which nutritional supplement is correctly paired with the health issue it addresses? which nutritional supplement is correctly paired with the health issue it addresses? vitamin c supplementation prevent depression. calcium supplementation increases iq. vitamin e supplementation prevent birth defects. vitamin b12 can vegans maintain health?