What does the positive pressure from the MK 20 Mod 0 help to do?

The positive pressure from the MK 20 Mod 0 plays a crucial role in preventing leaks within the diving system. When the system is under positive pressure, it ensures that water cannot enter the suit or helmet, effectively sealing off any possible ingress points. This is vital for maintaining the diver's safety and comfort, as it helps to keep them dry and protects against water-related hazards, including drowning risks in the event of leaks.

While the other options relate to potential benefits, they do not fundamentally capture the primary function of the positive pressure in this context. Enhancing air flow might be a secondary outcome depending on the configuration, but it is not the main purpose of the positive pressure. Similarly, reducing weight and enhancing visibility are not directly related to the role that positive pressure serves in the system. Thus, the correct understanding lies in recognizing that the primary function of positive pressure is to create an effective seal against water ingress.