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.
138Metamorphism is the isochemical process by which rocks are changed by either heat or pressure, or both heat and pressure. The chemical composition of the parent rock will be the same as the metamorphic rock produced.The rock undergoes the very slow process of solid-state recrystallisation without melting.ifferent temperatures and pressures cause new minerals to grow in rocks that have the same composition. The minerals produced are directly related to pressure and temperature conditions. The lower temperature limit for metamorphism is between 200 and 150 o C. Below these temperatures, changes are part of diagenesis.