These spoilers when acting as ________ destroy lift and induce drag to decelerate the aircraft or increase descent rates.

The term that fits best in the blank is "Speedbrakes." Speedbrakes are designed specifically to increase drag and reduce lift when deployed, which helps decelerate the aircraft or increase its descent rate. When speedbrakes are extended, the airflow over the wings is disrupted, resulting in a reduction of lift produced by the wings. This immediate effect is particularly useful during landing or in approach phases when pilots need to decrease speed and enhance the rate of descent without significantly altering the aircraft's configuration for landing.

Other options, such as elevator flaps, rudder controls, and aileron dampers, serve distinct purposes related to pitch control, yaw control, and roll damping, respectively, and do not perform the function of decelerating the aircraft or increasing descent rates through the increase of drag like speedbrakes do. Therefore, the proper identification of speedbrakes as the correct answer is based on their specific role in controlling flight dynamics during descents and speed management.