This is because they appear in series. Comic books Comics are the most common of the lot because they are appear in papers and many of us as students have read comic books.
Comics also have a biggest market.
I also think that comic strips are better that single pannel cartoons because the same thing is given more space and more room for expression. These are a few of my comic strips. The LOKI comic strip is named after the semi God of mischief belonging to the Scandinavian Mythology.