posted by John .
The bar graph below show the TV viewing habits of Koreans.
What is the part of speech of 'below'? Is 'which is' omitted before 'below'?
The word "below" can be either an adverb or a preposition.
In this sentence, it's an adverb. It's telling WHERE something is.
You could rephrase the sentence to include "which is" where you indicated, but it's not necessary.