Which sentence does not contain any punctuation errors? a. miss wallace, our babysitter, tried to open the pickle jar. b. miss wallace our babysitter, tried to open the pickle jar. c. miss wallace our babysitter tried to open the pickle jar.

A is the correct answer 

Hope this helps :)

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.