Question

what is phobos and earth crust

Answer 1

The planet is made up of three main shells: the very thin, brittle crust, the mantle and the core. The core forms only 15 percent of the Earth'svolume, whereas the mantle occupies 84 percent. The crust makes up the remaining 1 percent. The composition of the crust is quite different from that of the Earth as a whole.