Answer:
c. a potential decrease in the species of fish
Step-by-step explanation:
Dams block the migration of fish, deplete oxygen from rivers, and interfere with the biological triggers that guide fish. They also reduce self-cleaning ability of rivers. Due to the construction of dams and other factors, the population of freshwater fish species declined 37% between 1970-2008 - more than the populations of all other ecosystems. Populations of tropical freshwater fish species declined by as much as 70%.