How long will it take to build? How much concrete is needed? How will the lake be used for recreation? How will the dam affect fish populations?
I am hesitating between 4 options to answer the following question, which option should I choose?
Question: A city wants to build a dam nearby to increase water supplies. Which question is most important to ask about the environmental effects of building the dam?
Possibilities:
- How long will it take to build?
- How much concrete is needed?
- How will the lake be used for recreation?
- How will the dam affect fish populations?

How will the dam affect fish populations?