Which one of these protein structures shows the folding of the polypeptide which is held in place by interactions between R groups by H, ionic, and covalent bonds as well as strong disulfide linkages.

nucleic acid molecules are incredibly complex, containing the code that guarantees the four different nucleotide units comprise dna, the nucleic acid of interest to the genealogist. and one of four nitrogen-containing molecules called nucleotides

only about ten percent of the energy at one trophic level is passed on to organisms at the next trophic level. the remainder of the energy is used in life processes or lost as heat.