The first living things to live in an are are*
O
pioneer species
O
runoff
O
groundwater
O
succession

Pioneer species

Explanation:

Pioneer species are organisms that are first to colonize and area that is barren, or an area that was heavily disrupted. It could have been disrupted by natural disasters like volcano eruption or a flood. These organisms can grow on bare rock, which (with some help from wind and water) weathers the rocks and create soil. The soil formed eventually allows other forms of life, like plants to move in the area.

the answer to this question is 3.

the ratio of the conjugate base to the acid required to attain the desired ph.