This type of coma is usually reversible once the blood sugar is corrected. Oxygen deprivation: Oxygen is essential for brain function. Cardiac arrest causes a sudden cutoff of blood flow and oxygen to the brain, called hypoxia or anoxia.
The external power supply is the AC power adapter that converts household AC electricity voltages to the much lower DC voltages needed to charge a mobile phone's internal battery.
An externality is defined as a benefit or cost that is imposed on a third party, such as society, other than the producer or consumer of a good or service, or, more simply, an economic side effect. The more of a product that is consumed or produced, the more of an externality that results.