Identify five pieces of literature (of any genre) and place them on a scale from most to least in terms of the amount of research you would need to do on the cultural/historical background. Why would one work need the least research for you to read it meaningfully? Why would another need the most such background information? Why would the others be in the middle?

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.