Final answer:
When the orca's elevation increase of 7 m is added to its initial elevation of -6 m, the final elevation is 1 m relative to sea level.
Step-by-step explanation:
If an orca starts at an elevation of -6 m relative to sea level and its elevation increases by 7 m, we calculate the final elevation by simply adding the increase to the starting elevation.
-6 m + 7 m = 1 m
Therefore, the orca's final elevation relative to sea level is 1 m.