What is the main idea of this passage? The dam had little impact on the region.
The dam helped the entire region grow.
The dam had both positive and negative effects.
The dam did not have any effect until many years later.

if I'm sure the main idea is about the postive things that the dam has toward everything instead of the negtive stuff if im correct it does list that it has negtive effects but its talking about all the good things such as it did little things to hurt it helped the region and it didnt effect later on. hope this helps :)

Explanation:

raw information is your answer

~courtney