Material creates context and allows the audience to take the material and relate it to other things that can create a story and meaning. Material also aids the creation process if not using the correct rock or wood for a sculpture/ carving it could be harder to create and have less of an impact on the meaning. Finally, materials give life and feeling to art, if an artist uses real human blood for something it makes something feel gory and feels uncomfortable because as humans, we relate to it because its from our body. Other materials that are identified with an action can give it meaning, like raw bark/wood can make us feel something relating to nature.