Words or phrases that show relationships between ideas are called:

a. modifiers

c. transitions

b. articles

d. prepositions

I am not sure if you meant to put b. transitions, or c. transitions, but it is transitions because transitions prompt the reader that you are comparing or contrasting between ideas.

Example: Blue is masculine color, however, many girls like the color blue. I used the transition word 'however' to show that even though blue is a masculine color, girls like it too.