For sig figs, you count the total number of numbers that aren’t 0, you only count 0 if they are after a decimal point. since there is not a decimal point, there are 2 significant figures, answer A
Humans knowingly create environmental disasters?
This is a chemical change because there is a new substance that was created and the new chemical can cause other chemical reaction to happen compared to the 1st state of chemical that was in the cave. Because the cave water was exposed to another environment, the calcium bicarbonate, which is also known as salt. When the cave's groundwater was exposed to a different environment the atom in the cave water rearranged and crystallized.
Because it requires lots of electricity to turn it into an aqueous solution so that electrolysis can be performed on it.