Answer: B.) More research is needed to reach a conclusion, including related variables
Explanation:
As it is evident that oxygen is necessary element for living beings. It is required for the process of respiration, in which the food particles are broken down in the presence of oxygen into simpler substances.
Applying this knowledge to the given study suggests that all organisms require oxygen which can be less or more depending upon their habitat either in the shallow waters or in the depths. This conclusion is invalid and requires more explanatory approach which can be achieved by more research so as to derive a valid conclusion in which the two variables oxygen and relative habitats can be compared.
C) Natural selection
When something happens in nature and something changes all of a sudden, the animals tend to adapt to what gives them more chances of survival. As a result, a large amount of the population would attempt to adapt in a way that helps them survive.
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