What covers 75% of the earth and has the ability to deteriorate CaCO3, the same material our bones are made up of? Our oceans!

Here’s the chemistry crash course you didn’t ask for: Acidity is measured in pH on a scale of 0 (most acidic/least basic) - 14(most basic/least acidic). Each number on the scale indicates a 10x difference in acidity or alkalinity. Something with a pH of 1 is 10x less acidic than something with a pH of 0. Liquids become more acidic with the presence of positive Hydrogen Ions (hydrogen with less electrons).