Question: why do worms have know brains

Fiona Hatch answered on 14 Mar 2012:

Instead of a brain, worms have things called ganglions. Ganglions are made up of nerve cells, same as a brain, but they are much smaller and very simple. These work to help the worm move and allows it to detect things in the soil around it.

Interesting fact: Worms usually have a few ganglions that go down the whole length of their body! A bit like a spinal cord!