Answer:
Competitive exclusion occurs when " organisms attempt to fill the same niche"
Explanation:
mostly due to the fact that they are competing over the same food source, which is always limited in some way.
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Atom is the basic element of all living things because it's small. It is the smallest constituent unit of matter which has the properties of a chemical element. They are very small. Sizes are about 100 or 100, 000 fm. They are unstable. They are composed of a nucleus and electrons.
The answer is B, sameness