While bones are in vanilla minecraft and drop from skeletons, bones in Evil Minecraft have many more functions. For one thing, bones can be obtained on peaceful mode now since they can obtained by mining the Fossil block. When broken, fossils will give 1-2 bones. With bones, you can make bone tools and armor. These are similar to iron tools in terms of protection for the armor and speed/mining ability for the tools. Bones still have their vanilla minecraft abilities since Skeletons still drop them and they can still be used for bone meal.