Is there a relationship between the mass and volume of an object?

Yes, they both represent the amount of matter in an object/substance.

One physical characteristic of a substance is its density. Density is defined as the mass per unit volume of a substance. Density can be determined experimentally by measuring the mass of the substance and by measuring its volume. Gas and liquid densities are dependent on temperature.

Volcanoes make new rocks so not ahotspots are the the stuff that makes volcanoes mid atlantic ridge(mar cause i’m lazy) is a constructive plate boundary so it makes sense that new rocks would be found near it, also the mar is in the middle of the ocean so it fits the description deep ocean trench, umm, there’s no ocean trenches to where you’re goingso the mar is most likely the answeri wouldn’t trust me but hey why not