Which of the following factors is critical for preventing carburetor icing?

Monitoring temperature and humidity is crucial for preventing carburetor icing because these factors directly influence the likelihood of icing conditions forming. Carburetor icing typically occurs when there is a combination of high humidity and low temperatures, particularly when the air is drawn into the engine at a speed that causes a drop in pressure and temperature. This drop can cause moisture in the air to freeze, leading to ice formation in the carburetor and subsequent problems in engine performance.

Understanding the environment by keeping an eye on temperature and humidity helps pilots anticipate the risk of icing, enabling them to take preventive measures, such as altering their flight path or adjusting the engine settings, to mitigate the risk. Monitoring these conditions is essential for effective decision-making and ensuring safe operation of the aircraft in varying weather scenarios.

In contrast, while other factors such as altitude, airspeed, and fuel mixture adjustments can influence engine performance and efficiency, they do not directly address the immediate risk of icing in the carburetor as effectively as monitoring temperature and humidity does.