Here's a problem to solve: Scientists count and record the population of a particular fish in a lake that is losing water each year. What are they most likely trying to understand?

Among the 4 following options, which is the correct answer?

- A: How many fish are surviving the changing environment?
 
- B: How have changes in weather affected the water level?
 
- C: How much weight have the fish gained over the year?
 
- D: How is the plant life in the lake adjusting to the changes?
 