Ally knows that humans play a role in the carbon cycle. Enter the sentences that show how humans affect the levels of carbon dioxide in the air. During the carbon cycle, producers use carbon to make food. Consumers eat other organisms and take in their carbon compounds. Organisms break
down carbon compounds in their food and release some carbon dioxide. Decomposers break down the remains and wastes of organisms and
release carbon compounds into the soll. Some carbon is also added back into the cycle when fossil fuels and plant-based fuels are burned.
The sentences are

- 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