Dna from any source contains about the same amount of guanine

Cytosine

Explanation:

DNA come in base pairs. According to the Chargaff's rule on base pairs, DNA base pairs come in a 1:1 ratio. The base pair of guanine is cytosine (Adenine pairs with Thymine). The 1:1 ratio indicates that for every 1 guanine there is 1 cytosine. So this means that there is an equal amount of guanine and cytosine.

d is the answer

sorry if its wrong!

hydroxyl -oh

alcohols, always polar, can form hydrogen bonds with h2o molecules

carboxyl -cooh  

cargoxylic acids, has acidic properties which is a source of hydrogen ions, found in cells in ionized for with a charge of oh-1

carbonyl > co

ketone if within skeleton, aldehyde if group is at the end of skeleton, k & a may be structural isomers, it determines 2 sugars (ketose & aldose)

amino -nh2

amines, acts as a base, it can pick up h+ ions from surrounding solution, ionized with charge of 1+

methyl ch2

addition to rna/dna affects and gene expression

phosphate -opo3 ²⁻

organic phosphates, contributes to negative charge to, molecule that it is a part of, and potential to react with h20

sulfhydryl -sh

thiols, cross-linking stabilize the protein, and it is structure