Answer: Marina Trench
Explanation: The Mariana Trench stretches 2,500 kilometers (1,500 miles) in an arc that is edged by islands such as Guam and Saipan. Its deepest point is known as the Challenger Deep.
Answer:
1) Recursive definition: 
2) At the beginning of the 4th interval
Explanation:
1)
The initial population of the bacteria at time zero is

Here we are told that the reading is taken every two hours; we call this time interval "n", so

And also, after every time interval n, the number of bacteria has tripled.
This means that when n = 1,

And when n=2,

Applied recursively, we get

And substituting p0,
(1)
2)
Here we want to find at the beginning of which interval there are

bacteria.
This means that we can rewrite eq.(1) as

By simplifying,

Which means that

However, this means that the number of bacteria is 1,350,000 after 3 time intervals; therefore, at the beginning of the 4th interval.
Answer:
A and D I think
Explanation:
It's not erosion, so that is out of the answer choices. And I doubt it is crystallization, so that is why I think it is A and D. (correct me if I am wrong.)
Not sure but i think cohesion forces