I’m gonna go with answer D.c because the ocean had very deep trenches
It is 5.4 miles above sea level
Answer:
The Flowing of water on the land makes channels on the planet Mars.
The flowing of water is the geologic process that could have formed the channel on Mars. We can say that the flowing of water on the land made the channels on Mars just like on the earth. When the water flows for a long time from the same area, it takes the sediments and makes channels so we can say that the flowing of water makes the channels on Mars.
Answer:
The required efficiency of BOD5 removal of the plant needs to be at least 91%
Explanation:
Even though a WWTP (Waste water treatment plant) has several unit operations, it needs to have an overall treatment efficiency. In this case, it is only required to know how much BOD5 do we need to lower by removing organic matter from the water. It goes as following:

This will work for any efficiency, for any parameter you need to define. They need to be in the same concentration unit, of course.
Replacing known values, we have:

Which we will approximate to 91%, because decimal percentages do not say anything and are not currently used.