A Only one variable changed
The correct answer that would best complete the given statement above would be the term ADAPTIVE RADIATION. African cichlids are a group of closely related fish species. There are at least 500 known species living in three small lakes. Over time, specialized teeth and body colorations have evolved for each species in response to mutations and competition for food and mates. This change over time is an example of ADAPTIVE RADIATION. Adaptive radiation by definition, is <span>the diversification of a group of organisms into forms filling different ecological niches.</span>
Answer: During vigorous exercise your breathing rate increases in order to intake more oxygen
Explanation: during vigorous exercise / activity the body needs more oxygen in order to produce energy so your breathing rate increases in order to reach the demand of more intake of oxygen , and your muscles work harder due to an increase in oxygen demand and how much oxygen the muscles take from the blood during vigorous exercises , BUT during rest we have normal rate of oxygen intake because your body is at rest at that moment .
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Answer:
most common samples used today Blood and Hair