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.
Vocabulary/Definitions. 1  cap rock: A very hard, impermeable rock that traps methane and oil under the ground. 2  core: A long, thin sample of rock taken from deep below the Earth's surface. 3  fossil fuel: Energy-rich substances that have formed from the Earth's long-buried plants and microorganisms.