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.
The external environment, as agreed upon by Aharoni, Maimon & Segev (1978) and Daft & Samson (2009), can be defined as all elements that exist outside an organisation that may or may not affect aspects of the organisation.