Cells<span> need a source of </span>energy<span>, they </span>get<span> this </span>energy<span> by breaking down food molecules to release, the stored chemical </span>energy.This process is called 'cellular<span>respiration'. The process is happens in all the </span>cells<span> in our body. Oxygen is used to oxidize food, main oxidized food is sugar(glucose).</span>
The esophagus has a simple but significant functions to animals who has it. These functions can be a) to swallow food and serve as a passageway to the stomach and b) may serve to release the eaten food that might have some harmful compositions or chemicals -the vomit response.
Competition will increased because more organisms will be competing for resources
14 should be B if I can remember correctly, 15 is C