You are approaching another boat. Assume that according to the navigation rules,
you are the stand-on boat. Which exception to the rules means you must give way?

You have to give way if the give-way vessel has lesser maneuverability when compared to your vessel, is in a bad condition or simply if the give-way vessel does nothing to avoid an imminent collision.

Explanation:

In the rules for water body navigation, there are two vessels involved. first is the stand-on vessel which is expected to maintain its speed or course, and the give-way vessel that is expected to make an early its course or speed or a combination of both, or any other action to prevent collision between both vessels.

heat from the core of the earth causes convection currents to occur in the mantle. these currents slowly move the crust around.