In other words, i will follow your advice and guard my heart—you do the same. you are a good teacher, but you are beginning to sound a little preachy. i believe hamlet's affection is real, but i will watch myself around him. you may think i do not appreciate your good advice, but i do.

The correct answer is option a.

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.