Answer:
The answer is C
Explanation:
Nutrients (Nitrogen, Phosphorus, and Potassium) They are the third most frequent stressor in impaired rivers and streams, and the fourth greatest stressor in impaired estuaries. The three primary nutrients in manure are nitrogen, phosphorus, and potassium.
Answer: An area with lots of different kinds of plants and animals.
Explanation:
Vertebrates and invertebrates
Answer: C
Explanation: The process that occurred in the lake is natural selection. In the presence of an external environmental influence such as pollution, only the trouts that were fit to survive or in other words those that have the alleles that help in adapting to the new conditions live and increased in numbers. In such a case, one can say the fittest of the organisms survived and the corresponding allelic frequency in that population increased over time. The organisms carrying the other alleles died due to pollution and hence the overall frequency of alleles change.
Answer:
The pressure differences on either side of the valve.
Explanation:
The heart valves open and close passively because of pressure differences on either side of the valve. When pressure is greater behind the valve, the leaflets are blown open and the blood flows through the valve. However, when pressure is greater in front of the valve, the leaflets snap shut and blood flow is stopped.
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