No one answers my Questions :( Please help its my last one:

Name three sources of atmospheric carbon dioxide. (Write in complete sentences and be very detailed.)
This is science.
First and best answer gets 5 stars, a thanks, and a brainliest!

Doing this because I know I'm kickass at Chemistry.

One source would be human emissions. As humans, we use a lot of machines (like power plants) that produce large amounts of carbon dioxide into the atmosphere. The ocean also produces a lot of carbon dioxide via the evaporation cycle. Polluted waters eventually will go into the atmosphere. Volcanoes, even when not erupted, emit a lot of carbon dioxide as well. Dormant underground magma releases carbon dioxide through the Earth's pores, and even when a volcano erupts, it produces carbon dioxide as well.

- 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