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.

- calcium has greater affinity to bond with electron receptors than hydrogen does and hence, it has the ability to replace hydrogen in most of its compounds.

- lithium has 2 valence electrons in the product because it can make only 1 bond with hydrogen. beryllium has 4 valence electrons in the product because it can only make 2 bonds. it has fewer electrons than neon and can react with electron donors. each hydrogen has 2 valence electrons, the same as helium.

- the covalent bond formed between carbon and hydrogen is polar because carbon is more electronegative than hydrogen and it attracts the bonded electron pair closer to itself, thus giving hydrogen a partial positive charge.

- a hydrogen bond is a relatively weak bond that hydrogen atoms make with the electronegative atoms nitrogen, oxygen or fluorine.

so the best choice is a.) 2 calcium (ca) atoms

lol idk man i guess u gotta ask bill nye the science guy