Building Blocks of Nucleic acids are polynucleotides- <span>long chainlike molecules composed of a series of nearly identical building blocks called nucleotides</span>
Proteins are large biomolecules, or macromolecules, consisting of one or more long chains of amino acid residues
The answer to number 6 is a.
The answer to this question would be: vitamin
Some bacteria can produce vitamin K2 in the intestine. Other bacteria also able to change vitamin K1 into vitamin K2. But the amount produced is not much, so human still need to fulfill it from the diet. Vitamin K has a role in calcium regulation and in blood clotting pathway.
i believe the answer is "A fundamental role". hope this helps.