Which of the following describes the use of spoilers on wings?

Spoilers are high-lift devices primarily used on the wings of aircraft to help manage their performance during various flight conditions. When deployed, spoilers serve to disrupt the smooth airflow over the wing's upper surface. This action leads to a reduction in lift and an increase in drag.

The main purpose of spoilers is to decrease lift, which is particularly beneficial during descent and landing phases of flight. By reducing lift, spoilers enable pilots to control their descent rate and provide a more stable approach to landing. The increase in drag created by the deployment of spoilers also assists in slowing down the aircraft, making them essential for safely landing at an airport.

In contrast, the other options describe functions that are not aligned with the operational role of spoilers. Enhancing lift or increasing thrust are not characteristics of spoilers; they are designed primarily for managing lift and drag. Similarly, streamlining airflow over the wing does not fit the function of spoilers, as their deployment disrupts airflow rather than enhancing it.