How will you ensure that ecological balance is maintained in your ecosystem?

Explanation:

Taking steps to reduce or eliminate pollution from nonpoint sources such as streets and farms will help to maintain the ecological balance. Sewage and run-off of agricultural fertilizer can cause the rapid growth of algae in lakes and streams. The growth of algae blocks sunlight and depletes the oxygen in the water.

the answer for apex is "1 and 6"

explanation:

on disadvantage of hydroelectric power is the cost. another disadvantage of using hydroelectric power is finding a water source powerful enough to harvest hydroelectric power.