We have a pond in our neighborhood. It's just a little pond, but there are two ducks who live there. One of Kelsey's highlights in life is to go feed the ducks. Last night she was getting a little cranky, so I took her to feed the ducks, which of course cheered her up immediately!
After we ran out of stale bread, we began walking around the edge of the pond. There was a bunch of green gooey stuff floating along the banks. Kelsey said "Look at all that poop!" I said, "That's not poop, that's algae."
Without even hesitating, she looked at me and said (remember, she's 3) "I have allergies too, and my medicine is at home."