Which type of appeal is the author primarily using in this excerpt from "top of the food chain"?

The answer is ethos, it appeals to emotional states.

The correct answer is: a fluorescent

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.