Final answer:
The Climber's Estimate function is not provided, so we cannot determine the elevation at which the air pressure would be zero on Denali.
Step-by-step explanation:
The air pressure at the summit of Denali, the highest point in Alaska, can be estimated using the Climber's Estimate function. To find the elevation at which the air pressure would be zero, we need to find the point where the pressure equals zero in the Climber's Estimate function. Unfortunately, the Climber's Estimate function is not provided in the given information, so we cannot accurately determine the elevation at which the air pressure would be zero.