What is acid rain? What chemicals make rain acidic, and how does it happen? How does acid rain affect humans? Are there any health problems associated with acid rain?
What effect does acid rain have on trees and soil?
What happens when lakes and aquatic systems become acidic?
Are the aquatic systems in our area being affected by acid rain? If yes, to what extent?

When rain water has a lower pH(acidic) than usual it is considered acid rain.

Rain water becomes acidic when sulfur dioxide and nitrogen oxides are released into the atmosphere. They cause a chemical reaction with water, oxygen, and other chemical in the atmosphere to form sulfuric and nitric acids which then mix with water and fall down as rain.

Acid rain causes air pollution which can cause respiratory diseases. This can cause difficulty in breathing. Acid rain causes asthma, chronic bronchitis and pneumonia.  

Acid rain removes nutrient from the soil, trees need these in order to be healthy. It separates aluminum from the soil which destroy plant root tips, this makes it difficult for trees to take up water.

Acid rain reduces the pH of water in aquatic systems which is harmful to marine animals. It kills many fish and other creatures that fish eat. It separates aluminum from the soil which drains into water system. The  aluminium is toxic to fish in acid waters. It causes damage to the gill which effects the respiratory system of the fish and the fish dies.

Acid rain is affecting most of the places on earth.

c) 50% there are four chromosomes. after crossing over, 2 of the four have been changed. that means any gamete has a 2 in 4 chance or 50% chance of receiving the mutated chromosome.