Question

which environmental factor would cause the greatest decrease in the number of species of plants and animals living in some of the lakes in the united states? global warming increase in dissolved oxygen levels acid rain ozone destruction

Explanation:

To determine the environmental factor causing the greatest species decrease in lakes, we analyze each option:

• Global warming: Primarily affects climate, sea levels, and broader ecosystems. Its direct impact on lake species is less immediate compared to acid rain.
• Increase in dissolved oxygen levels: Higher oxygen is beneficial for aquatic life, promoting species growth rather than decline.
• Acid rain: Rain with high acidic content (from sulfur and nitrogen oxides) falls into lakes, lowering water pH. Most aquatic organisms have narrow pH tolerance; acidic water disrupts physiology, reproduction, and food chains, leading to significant species loss.
• Ozone destruction: Affects the ozone layer, causing UV radiation increase. Its direct impact on lake ecosystems is less direct than acid rain.

Thus, acid rain directly impacts lake water chemistry, harming aquatic species.

Answer:

C. acid rain