Though we will discuss this more in a future week, run-on sentences are created if you do not join two clauses correctly. Which one of these sentences is correct? You’re so kind I appreciate your help.
You’re so kind, I appreciate your help.
You’re so kind and I appreciate your help.
You’re so kind, and I appreciate your help.

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.