Trees = oxygen

This is what my 5-year-old niece has figured out.

As my sister is driving...

Kid, "Mommy, is Mars a star?"
Sis: "No, it's a planet. You can see it sometimes in the sky though like you can see stars."
Kid: "Oh. Could we live on Mars?"
Sis: "Well no we couldn't because we would have trouble breathing."
Kid: "Oh so there must not be any trees on Mars because if there were trees, we would have oxygen and could breath."

oh.
muh.
gawd.

really??????????she's a genius.