The answer is cholesterol
<span>Answer: a. take place in nuclear reactors
</span><span>Controlled nuclear chain reactions are the reaction in nuclear reactors. The reaction is controlled to make its rate slower. This will make the reaction relatively safer, so the energy produced can be changed into electricity in power plant. When the reaction is not controlled, it could cause explosive like in nuclear bomb.</span>
D. A struggle for existence is apparent.
If a struggle for existence is apparent, natural selection occurs because all of the weak/unfit/unadapted ones die.
Photosynthesis turns carbon dioxide and water into oxygen. The chemical change happends. It is an Endothermic reaction cause energy needs to be in and order for photosynthesis to happen. Then then the plant puts the food away for later lime in the winter or when it is dry
