Final answer:
The type of crust on the plate determines which plate will subduct. Subduction occurs when one tectonic plate is forced beneath another plate, typically oceanic crust converging with either continental crust or another oceanic crust.
Step-by-step explanation:
The property of matter that determines which plate will subduct is the type of crust on the plate. Subduction occurs when one tectonic plate is forced beneath another plate.
This typically happens when an oceanic crust plate converges with a continental crust plate or another oceanic crust plate. Oceanic crust is denser and more capable of subduction compared to continental crust.
As the subducting plate moves deeper into the Earth's mantle, it releases water from hydrated minerals, leading to the formation of magma and volcanic activity.