His sorrow goes / Like mountain snows / In waters sweet and clear,

a
repetition

b
metaphor

c
simile

d
onomatopoeia

e
hyperbole

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.

Iam not sure sorry