<span>It should be false, the crust is eventually cold and brittle for convection of currents to occur. The convection currents that is usually located at the magma drive plate tectonics. Warm produced from the radioactive rot of components somewhere down on the inside of the Earth makes magma in the aesthenosphere.</span>
The Cambrian explosion. Trilobites were found because of their hard shell, unlike soft bodied creatures.