Answer
Joseph's level after all of this is 121 feet below the sea level.
Step-by-step explanation
Joseph dove 47 feet below the sea level.
Current level that Joseph is at = -47
Then, they dove 137 feet further below sea level
Their current level is now = -47 - 137 = -184 (That is, 184 feet below the sea level)
Then, he and his dive partner swam up 63 feet in order to swim with the turtles.
Their current level is now = -184 + 63 = -121 feet (That is, 121 feet below sea level).
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