Tony Kersey, age 13, of Indianapolis, Indiana, for his question:

What does the appendix do for us?

In humans, the vermiform, or wormy, appendix seems to be no use at all. Some biologists suspect that it may have played a minor digestive role in our very remote ancestors. It may still be somewhat useful in the apes and large primates. In rats, the appendix is not a wormy vermiform organ. It is a sizeable portion of the intestine that performs as an organ of digestion.

The human appendix is a small tube that opens into the large intestine, on the lower right side of the body. Digesting material is always moving on its way through the body. Sometimes a small portion takes a wrong turn and passes down the one way tube into the appendix. If it stays there, it may become infected and the patient goes down with appendicitis. Nowadays, this is cured by an appendectomy, a rather minor piece of surgery that removes the useless appendix and sews up its entrance to the large intestine.