Teacher, what's a microbe?

I never thought, in a million years, that I wouldn't know one of the words that my elementary school kids were learning at their English Hagwon.  Although, today, I was proven wrong!  Check out this vocabulary list that one of my 5th graders had to memorize for her Hagwon test today.  

How in the world is microbe on the same level as pony, staple, and oven?  I don't even know what that means!!  Seriously, who makes these lists?!