By Mayo Clinic Staff. Erectile dysfunction â the inability to get and keep an erection firm enough for sex â is a common problem. You've likely seen advertisements for erectile dysfunction herbs or supplements to increase your sexual performance..
plate tectonics. In geology, a theory that the Earth's lithosphere (crust and upper mantle) is divided into a number of large, plate-like sections that move as distinct masses. See Notes at fault, Gondwanaland, See more at tectonic boundary.
Lithospheric Plates. The theory of plate tectonics states that the surface of the Earth is composed of a series of fractured plates. The fractured plates making up the crust of the Earth are called lithospheric plates . There are currently seven major lithospheric plates on the surface of the Earth.