The 10th grade biology teacher asked Jessica: "What part of the human body increases to 10 times it's normal size when excited?" Jessica responded: "I'm too embarrassed to answer!"

So the teacher asked Little Johnny who quickly said: "That's easy...the pupil of the eye." "That's correct, Johnny. Very good!"

And then turning back to Jessica, the teacher said: "I have three things to say to you, young lady... first, you didn't do your homework; second, you have a dirty mind; and third, you're in for a big disappointment!"