Which condition is characterized by a lack of blood supply to organs?

Shock is characterized by a significant reduction in blood flow throughout the body, leading to inadequate blood supply to vital organs. This condition can result from various factors, including heavy bleeding, severe dehydration, or a severe allergic reaction, among others. When the body's tissues do not receive enough oxygen and nutrients due to poor circulation, it may result in organ dysfunction or failure. Recognizing and responding to shock promptly is crucial because prolonged lack of blood supply can cause irreversible damage to organs.

In contrast, a stroke primarily involves the interruption of blood flow to the brain specifically, leading to neurological impairments. Heart failure refers to the heart's inability to pump blood effectively, which can cause fluid buildup and insufficient blood supply to various parts of the body but is not defined solely by a lack of blood supply. Cardiac arrest occurs when the heart stops beating effectively, leading to an immediate cessation of blood flow, but it is a sudden event rather than a condition characterized over time by insufficient blood supply. Therefore, shock is the most accurate choice when considering overall lack of blood supply to organs.