I want to grow a bonsai tree. Do I need a special type of seed or tree for me to be able to grow it as a bonsai tree?
You do not need a special type of seed or tree for it to be able to be grown as a bonsai. Bonsai trees are just normal trees that are kept from growing big.
There are certain types of trees that grow better as bonsai trees and are easier to keep small (and in a small pot) than others. These are however, still normal trees and not some special mini species of the tree.
When looking to buy seeds or saplings you can simply buy the type of tree you plan to grow. You do not need to buy a special 'bonsai' or 'mini' species of the tree.