Final answer:
The difference between a scuba diver swimming at -8 m and a shark at -29 m is 21 meters, calculated by finding the absolute difference between the two depths.
Step-by-step explanation:
To find the difference between two elevations, you subtract the lesser elevation from the greater elevation. Given a scuba diver swimming at an elevation of -8 m and a shark at an elevation of -29 m, the difference in elevation is:
-8 m - (-29 m) = -8 m + 29 m = 21 m
So, the difference between the diver's and the shark's elevations is 21 meters.