Acid rain:

* Acid rain is caused by the release of sulfur dioxide and nitrogen oxides into the atmosphere, which react with water vapor to form sulfuric and nitric acids.

* These acids can then fall to the ground as rain, snow, or fog, making the water more acidic.

Effects on trees:

* Acid rain can damage the leaves and needles of trees, making them more susceptible to disease and insect infestations.

* It can also leach nutrients from the soil, making it difficult for trees to grow.

* However, trees have some ability to tolerate acid rain, as their roots can absorb nutrients from deeper layers of the soil.

Effects on fish:

* Fish are much more sensitive to changes in water pH than trees.

* Acid rain can make water bodies acidic, which can directly harm fish, making it difficult for them to breathe and reproduce.

* Acidification can also release aluminum from the soil into the water, which is toxic to fish.

* Fish eggs and young fish are particularly vulnerable to acidification.

Conclusion:

While acid rain can harm both trees and fish, fish are generally more sensitive to the effects of acidification. This is because they live in the water, which is directly affected by acid rain, and they are less able to tolerate changes in pH than trees.