Which sentence uses parentheses correctly? A)
She is our salutatorian this year (I am so proud of her)!
B)
She is our salutatorian this year. (I am so proud of her!)
O
She is our salutatorian this year. (I am so proud of her.).
D)
She is our salutatorian this year (I am so proud of her!).

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.