Rivers and the aquatic life that live within them can change over time due to human activity and natural forces. Which of these changes would likely have the greatest effect on a river system? (SC.912.L.17.20) *

Question

1 point
A city being built near the mouth of the river.
A bridge that crosses the river high in the mountains.
A change in the salinity of the ocean into which it flows.
A dam on the river near where it flows from the mountains.

Answer 1

The change that would likely have the greatest effect on a river system is:

A dam on the river near where it flows from the mountains.

Dams can significantly alter the flow of water, change sediment transport, affect water temperature and chemistry, and have major impacts on aquatic habitats and species both upstream and downstream. This can lead to significant ecological changes, including alterations in fish populations and other aquatic life.