Which of the following represents a direct effect of acid rain?

Acid rain is a result of industrial emissions that release sulfur dioxide and nitrogen oxides into the atmosphere. When these gases react with water vapor, they form sulfuric and nitric acids, which then fall to the ground as precipitation. This precipitation alters the pH of lakes and rivers, leading to a phenomenon known as lake acidification.

The direct effect of acid rain on water bodies is the lowering of pH levels, which can be detrimental to aquatic life. Many species of fish and other aquatic organisms are sensitive to changes in pH levels. Acidic waters can lead to increased toxicity of certain metals, disruption of nutrient availability, and overall harm to the structure of aquatic ecosystems. Consequently, this impacts biodiversity in aquatic environments, affecting species composition and the health of the ecosystem.

In contrast, options such as the promotion of biodiversity or improvement of plant health do not accurately represent the harmful impact of acid rain, as the overall effect tends to be negative, leading to declines in both aquatic and terrestrial biodiversity. Increased soil moisture is also not a direct consequence of acid rain, as the precipitation itself can result in detrimental effects on soil chemistry and health. Therefore, the impact of acid rain on aquatic life through lake acidification clearly captures the essence of the question concerning