<span>Stents help keep coronary arteries open and reduce the chance of a <span>heart attack.</span></span><span><span>The stent holds the artery open and allows blood to flow more freely.</span> </span>
drought, smog, flooding, volcanic eruption, blizzards, and pollution
Answer:
The null hypothesis is incorrect.
Explanation:
The null hypothesis is incorrect because the average number of bacteria did not remain the same at the source and at the outlet. We know that bacteria reproduce in a very less time and they use reproduction methods such as binary and multiple fission so with the passage of time, the population of bacteria increases and did not remain the same at the source and at the outlet.
The answer is B. and D. they contain plants that purify the water and they take habitats away from animals.