The 6th grade science teacher asked her class
“Which body part increases to 10 times its size when
stimulated?”
No one answered for a long time until little Mary
stood up, angry and told the teacher that she was
going to tell her parents, who would tell the
principal, who would fire the teacher! The teacher
ignored her and asked the question again,
“Which body part increases to 10 times its size
when stimulated?”
Finally Billy stood up and said that the body part
that increases 10 times its size when stimulated is the
pupil of the eye.
The teacher said “Very good, Billy.
Then she turned to Mary and said, ”As for you, young
lady, I have three things to say:

1) you have a dirty mind,
2) you didn't read your homework, and
3) one day you will be very, very disappointed."