Respiration is the chemical reaction that break down nutrient molecules in living cells to release energy .
in humans and other living organisms except plants, our cells need energy ATP for muscle contraction and for cell division to repair damaged tissues and growth ,also for active transport which involves movement of molecules across a cell membrane against a concentration gradient.
Normal cells<span> listen to signals from neighboring </span>cells<span> and stop growing when they encroach on nearby tissues
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didnt understand the question, but the answer i think would be
The eukariotic cell cycle
No, although there are several theories with increasing evidence, there is still no way to know for sure how it occurred. The great mystery of the beginning of universe is way too vast and vague. Theories can only be proven by presenting a solid proof, but great creations such as universe itself doesn't have to be solved. Various possibilities must have happened or there must be a one conclusion leading to its existence; but moreover, it is not our problem to solve. The confirmation of beginning of its existence will only feed the curiosity of humans.
