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.

b. the carbon cycle ensures living things have a source of hydrogen

there are mainly three domains in biological classification namely; archaea, bacteria, and eukarya.

archaea includes all the prokaryotic cells which are characterized by their lipid membranes. they have branched hydrocarbon which is attached to glycerol through an ether linkage.

bacteria includes all the prokaryotic cells, the cell membrane of which are made up of the unbranched fatty acid chain. in addition, they are attached to glycerol through an ester bond.

eukarya includes all the eukaryotic cells, that is, the cells contain a nucleus and other membrane-bound cell organelles.

they can be autotrophic as well as heterotrophic, unicellular as well as multicellular

they include kingdoms like protista, plantae, animalia, fungi et cetera.

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