Scientists believe that plate tectonics is an example of an internal force that changes the earth's crust. There are about seven or eight plates that make up the Lithosphere of our earth. The Lithosphere is the hard outer crust of our planet earth and this is the one that is broken up into a number of tectonic plates. <span />
Because if there are no plants the animals move , adapt, or die and if there are a lot of plants there tends to be a large ecosystem
