Hi, i had a lot of trouble with this one:

Explain the significance of the difference in color and its relationshiip to the convolutions.

We are doing the brain so, maybe you can use that use to help me please, thanks

I'm not sure what information you are seeking. By "convolutions," are you referring to the gyrii (hills) and sulcii (valleys) of the brain surface? Are you referring to the white color of the myelin sheaths around the axons and the grayish color of the cell bodies of the neurons? The cell bodies are more likely to be on the surface of the brain. The convolutions allow more surface area to be obtained within the constricted area of the skull. (It is like crumbling up a sheet of paper to make it fit into a small area.)

Since this is not my major area of expertise, I searched Google under the key words "brain convolution color" to get these possible sources:

http://en.wikipedia.org/wiki/Brain
http://books.google.com/books?id=PMdwWTdBpOYC&pg=PA67&lpg=PA67&dq=brain+convolution+color&source=web&ots=aaKf8e7NQa&sig=WqRd_3_yjgsujr_yvfvksiYcbmk
http://books.google.com/books?id=tpqtQr2wD1wC&pg=PA176&lpg=PA176&dq=brain+convolution+color&source=web&ots=lgj7fcoQoT&sig=uW3JMYrjZfimACXO1bKDLLXJxbM

I hope this helps. If not, repost with more specific questions. Thanks for asking.