Two or more things, the reader must consider how the things are different ?

Two or more things that the reader must consider that things are different is that in (1) in itself, things have its own complexities and uniqueness. Try to segregate things that is common in two things. You can make a Venn Diagram so that it's easier to see the similarities and differences. (2) Take note of the certainty of their uniqueness in a way that you are referring to that same field.