Question

question 4 of 20 : select the best answer for the question. 4. how does the hydroelectric dam pictured here impact the environment? a. by releasing toxic chemicals in their emissions b. by blocking fish migration c. by producing greenhouse gases d. by generating significant heat that artificially warms nearby water mark for review (will be highlighted on the review page) << previous question next question >>

Explanation:

To determine the environmental impact of a hydroelectric dam, we analyze each option:

• Option A: Hydroelectric dams don't emit toxic chemicals as they generate electricity using water, not combustion. Eliminate A.
• Option B: Dams create barriers in rivers, which can block fish migration (e.g., salmon moving upstream to spawn). This is a known environmental impact of dams.
• Option C: Hydroelectric power is a low - greenhouse - gas - emitting energy source compared to fossil - fuel - based power. Dams don't produce significant greenhouse gases in the way described. Eliminate C.
• Option D: Hydroelectric dams don't generate significant heat to artificially warm nearby water. Their operation is based on water flow and pressure, not heat generation like some power plants (e.g., nuclear or coal - fired). Eliminate D.

Answer:

B. By blocking fish migration