Answer:
He has to travel 1245 feet upwards from his current level.
Explanation:
Given that a United States Navy diver is a specialized suit is swimming at a height of - 1245 feet relative to a sea level.
That means the height at which the diver is specialized in swimming is 1245 feet below sea level.
Therefore, if the diver wants to go back to the sea level then he has to travel 1245 feet upwards from his current level. (Answer)