Scenario 1: A river in North Carolina has been tested and the following data is obtained: pH = 7.1
Dissolved Oxygen = 7 mg/L
Nitrates = 8 mg/L
Phosphates = 0.03 mg/L
Biotic Index = 3.5
What is the overall quality of this river? How do you know? If the quality is low, what do you think could be happening in the environment to cause these readings?

Good.

Explanation:

The overall quality of this river is good because all the levels is in normal range. Healthy water should have 6.5 to 8 mg/L of dissolved oxygen concentrations, normal range of phosphorus is 0.005 to 0.05 mg/L, levels of nitrate at or below 10 mg/L and the biotic index less than 3.75 is considered normal and the data shows all value of substances comes in normal range so we can say that the quality of water is good.

correct answer is option a.

tropopause, stratopause and mesopause have all in common aspect that is point of maximum temperature in its layer of the atmosphere. all layers of atmosphere observe abrupt change in temperature. tropopause is the boundary between troposphere and stratosphere. stratopause is the boundary between stratosphere and mesosphere. mesopause is the boundary between mesosphere and thermosphere. these all boundaries are ranges between altitude of 0 to 80 km.