Which component is essential for ensuring proper buoyancy control in the MK-20 system?

The buoyancy compensator plays a crucial role in the MK-20 system by allowing divers to maintain neutral buoyancy underwater. This device enables divers to control their buoyancy at various depths, which is vital for safety and efficiency during a dive. It is designed to be inflated or deflated with air, providing the diver with the ability to adjust their buoyancy in response to changes in depth or weight.

While the diving suit and weight belt are also important components of the diving system, they serve different functions. The diving suit provides thermal protection and physical coverage for the diver, while the weight belt assists in counteracting the buoyancy of the dive suit and equipment, helping the diver descend. However, without the buoyancy compensator, a diver would struggle to make fine adjustments to buoyancy, which is essential for stable underwater operations. The exhaust valve is important for expelling excess air from the buoyancy compensator, but it does not directly contribute to buoyancy control. Thus, the buoyancy compensator is the key component for ensuring proper buoyancy control in the MK-20 system.