compare a cell that has grown too large to be efficient with a wireless network that has too many users

the answer is "a.) well–developed vascular system."

explanation:

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

thinking it would be d not too sure but i think it's right