If you look at two species in their embryogenic stage. their bones and their forms look similar and you can differentiate too.
if you look at a fish and a human...
humans wont have the the fins protruding in the fishes embryo, showing how different they are. <span />
Filling of the heart and needing to pump the blood back out at an also increased rate
Answer: the dam cause no more fertile soil to enter in to farmers land for growing crops hope this helps :)
Explanation: this dam has caused a big change to the lifes of farmers downstream from the dam. Usually when the river flooded once a year before the dam was built. It deposited fertile soil from upstream on its banks downstream. This washed up soil was extremely furtile, and renewed itself every year at in flood season. But now, since the dam was built the annual flood has been stopped. Causing all the farmers downstream to have to use fertilizers to grow their crops, which makes it more expensive.