Cyanosis is characterized by which of the following symptoms?

Cyanosis is characterized by a bluish coloration of the skin, which occurs when there is insufficient oxygen in the blood or when blood flow is impaired. This bluish tint can be most noticeable in areas with thin skin, such as the lips, fingertips, and earlobes. The condition results from the deoxygenation of hemoglobin, which gives the blood a darker hue, leading to the visible discoloration of the skin.

The other options represent different conditions. Yellowing of the skin corresponds to jaundice, which is often indicative of liver dysfunction or other medical issues. Redness of the skin can be associated with inflammation, allergic reactions, or increased blood flow due to various causes. Paleness of the skin may indicate anemia, shock, or poor circulation, but does not relate to the specific condition of cyanosis. Therefore, the characteristic symptom of cyanosis is the bluish coloration of the skin.