Heredity maybe? im not really sure, thats all i could think of
I think it would be option 4?
Acid rain<span> is caused by a chemical reaction that begins when compounds like sulfur dioxide and nitrogen oxides are released into the air. These substances can rise very high into the atmosphere, where they mix and react with water, oxygen, and other chemicals to form more acidic pollutants, known as </span>acid rain<span>.</span>
Ok then! So mitosis is when a cell splits and doesn't lose/gain any chromosomes. In meiosis the chromosomes join and split evenly at the cell's "poles". Chromosomes will be lost evenly through this process.