Do a little searching, it's a well discussed topic. :jointsmile:

This should get you started.

http://boards.cannabis.com/recreatio...is-indica.html
http://boards.cannabis.com/recreatio...pros-cons.html

Those threads are about the differing highs. With regard to growing sativas grow taller with thinner fingers on their leaves whereas indicas grow stouter with fatter fingers on the leaves. Once you consider the height the width of the fingers makes sense because they're tailored for maximum light penetration. I don't know why they differ but they go hand in hand like that.

Pretty much everything you come across is a hybrid, usually in favour of indica, because few people want to grow a pure sativa indoors. Some seed sites will tell you what % indica and sativa the strain is.

-canuck :jointsmile: