Addiction: Central nervous system (CNS) stimulants are addictive, even if they are not abused. Many factors, including the patient's personal history, the type of stimulant that is being taken, the dose of the drug, and duration of use, influence how likely an individual is to become addicted.
The source of all waves - mechanical or electromagnetic - is something that is vibrating. Matthew Donovan.
Earth has two principal sources of energy: internal (coming from itself) and external (from the sun). Internal energy comes from radioactive decay and gravitational attractions which keeps Earth's interior warm and in turn, keeps Earth's surface warm.This drives plate movements for the tectonic plates.