Check all the characteristics below that describe elements
one type of atom
a pure substance
more than one type of atom
chemically combined elements
DONE

one type of elements

I hope it's helps you

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explanation:

idk

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