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.

answers: to make sure that all of the broken pieces of tablet were added to the water, to allow for fair comparison of all three trials, with different particle sizes to avoid experimental error