What's an account? When a computer is used by many people it is usually necessary to differentiate between the users, for example, so that their private files can be kept private. This is important even if the computer can only be used by a single person at a time, as with most microcomputers. Thus, each user is given a unique username, and that name is used to log in. There's more to a user than just a name, however. An account is all the files, resources, and information belonging to one user.
They include biochemical, clastic and evaporative sedimentary rocks. Biochemical sedimentary rocks are formed from organic processes that involve living organisms producing the sediments. These living organisms can be snails and clams whose discarded calcium carbonate shells can form limestone.
Metamorphic Rocks of Ring Mountain, Tiburon. At only 602 feet in elevation, Ring Mountain is hardly a mountain. But it is well known to geologist and biologist alike because of its unusual geology and the unique plants that grow in the serpentine soils on the Tiburon peninsula. Serpentine is a metamorphic rock: a rock changed by heat and pressure. The high concentration of magnesium and calcium in the soils is usually toxic to plants, but some rare plants thrive [see: http://www.marin.cc.ca.us/~jim/ring/rplant.html].