Answer:
C. Yes, because they have a definite composition.
Explanation:
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Answer : Option B) Lead
Explanation : Lead is chemical element which damages<span> the central nervous system, cardiovascular system, reproductive system, hematological system, and kidneys with overexposure as compared to other elements in the given option.</span>
The answer is D: studying how the mayfly population affects the number of trout in a stream <span> As the science of ecology studies interactions between individual organisms and their environments.</span>
