Crust (geology) Crust (geology) In geology, the crust is the outermost solid shell of a rocky planet, dwarf planet, or natural satellite. It is usually distinguished from the underlying mantle by its chemical makeup; however, in the case of icy satellites, it may be distinguished based on its phase (solid crust vs. liquid mantle). The crusts of Earth, Moon, Mercury, Venus, Mars, Io, and other planetary bodies formed via igneous processes, and were later modified by erosion, impact cratering, volcanism, and sedimentation. Most terrestrial planets have fairly uniform crusts. Earth, however, has two distinct types: continental crust and oceanic crust. These two
How the Snake Lost Its Legs many of the, "nuts and bolts of evolution, deeper than just natural selection," are on display in the book, revealing, "precisely what genetic/physiological mechanisms are being selected for." The molecular biologist Arnaud Martin observes that, "As children, we have all wondered about 'the How and the Why' of animal features, and if you are reading this it is in fact quite possible that a similar inquisitiveness still burns within you. The tone of "How the Snake Lost its Legs" finds its roots in the famous "Just So Stories" of Joseph Rudyard Kipling by tickling this curiosity with the formulaic "How