An acid is a substance is that produces hydrogen ion in an aqueous solution. Increasing hydrogen ion contents depict increase in acidic contents.
An Alkaline is a substance that produces hydroxide ion in an aqueous solution. Increasing hydroxide ion depicts increase in alkalinity.
Using a pH scales to measure the acidity or alkalinity of a substance has a range value of 0 to 14 . Decreasing pH value depict increasing acidity contents . 0 to 2 is very acidic 3 to 5 is moderately acidic and so on . 7 pH scale means the substance is neutral . From 7 upward depict increasing alkalinity.
Since the pH of rainfall change from 4.22 to 4.40 that means the acidic content decrease. The most acidic rainfall is 4.22.
Although the DNA packaging with histones proteins is mean to form nucleosomes (groups of 8 histones proteins), the higher structures why the genetic material is packaged with those molecules is to form chromosomes, as you said.
