Which term describes a bluish discoloration indicating low oxygen?

• A. Ischemia
• B. Ecchymosis
• C. Necrosis
• D. Cyanosis

Answer: (D)

Cyanosis describes a bluish discoloration of the skin and mucous membranes caused by reduced oxygen levels in the blood. It signals that oxygen saturation is low, often due to hypoxemia, so this term directly matches the description of a blue tint from inadequate oxygen.

The other terms refer to different concepts: ischemia means insufficient blood supply to tissues (not primarily a color change), ecchymosis is a bruise from blood trapped under the skin, and necrosis is tissue death from prolonged lack of blood flow or severe injury. So cyanosis is the correct term for the bluish indication of low oxygen.