Select the noun phrase to complete the sentence. after the race, the runner found

Okay, biology isn't exactly my strongest subject (it never has been), but i'm pretty sure the answer is nucleotides. dna is made up of nucleotides. each nucleotide contains a phosphate group, a sugar group, and a nitrogen base. there are four different nitrogen bases: adenine (a), thymine (t), guanine (g), and cytosine (c). a always pairs with t, and g always pairs with c.

D. because a physical change doesn't involve anything that's chemically changing the substance (when you think about physical change, think about stuff like color changes that doesn't change the substances chemical makeup)