All of the matter in the universe formed after the big bang. Scientists predicted that hydrogen and helium would be the most abundant elements.
What did scientists discover?
A. The universe has 74% hydrogen and 24% helium, which supports
the big bang theory.
B. Stars are made mostly of other elements, which supports the big
bang theory
C. The universe has 73% hydrogen and 25% helium, which does not
support the big bang theory.
D. Planets are made mostly of other elements, which does not
support the big bang theory.

The answer is A. Here is proof

Explanation:

- 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

a compound is a molecule made of atoms from different elements.

a. by the combination of an unlimited number of elements