This is a quick little unit that teaches children about living and non-living things. I find that most kindergartners can almost always tell you what things are living and what things are non-living, but they cannot tell you why. And there are definitely some tricky ones--for example, most of my kids think that a tree is non-living.
And then there is always the discussion of non-living versus dead. They will sometimes say things like, "The rock is dead." So I explain that in order to be "dead," something had to be alive first. And then, most likely, one of you little angels will shout out, "My grandpa is dead." Don't you just love kindergarten!