Which substance is a nucleic acid? a.)amino acid b.)fat c.)polysaccharide d.)rna

D.RNA is the correct answer.

Explanation:

RNA is present in living cells, and RNA is considered has as the first nucleic acid.

RNA molecule - first nucleic acid to carry the heredity information.

RNA's function: to store and express the genetic information before DNA enter the system.

RNA is a single strand, which controls protein synthesis and gene expression.

Thus RNA substance is a nucleic acid.

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