If Osa is in a submarine that is 200 feet below sea level and Jill is hiking a mountain and is at 311 feet above sea level, which person is closest to zero ground level?

Osa

Step-by-step explanation:

Relative distances

Osa is in a submarine 200 feet under sea level. We can say its distance to sea level is 200 feet

Jill is 311 feet above sea level, her distance to sea level is 311 feet

We can say Osa is closest to sea level

If we consider ground level to the reference where distances are measured from above, then we must say Osa is closest to it because she is below sea level and naturally, closer to the ground below it