The term 'They're Often Seen on Slides' can be solved by the two crossword solutions 'ameBAS' (6 letters) and 'AMOEBAE' (7 letters). Amebas and amoebae are both single-celled organisms that belong to the protozoa family. They are often seen on slides under a microscope due to their small size. Amebas and amoebae are known for their ability to move and change shape, which is why they are often studied in biology classes.