There is only One "thing" and it is spacetime.
Spacetime has characteristics.
Matter is only an appearance of energy in spacetime.
Matter is simply a spherical standing wave of energy.
The energy goes out in spherical standing waves to the limits of its inertia, then falls back to the center of the standing spherical wave where it again reverses into an out wave.
These in and out waves intersect with each other at the point where they combine, forming something like progressively larger "onion-shells" of energy around the center of the spherical standing wave.
An electron is a spherical standing wave which spins in one direction, while a positron (anti-matter) is identical except for its opposite spin. When an electron and positron meet they mutually annihilate, meaning that the bound energy in both "particles" is released back into the spacetime continuum. That's why matter/antimatter collisions are 100% efficient, no energy is lost, just redistributed.
It would take quite a long time to get there, but this is the sum of the matter:
"In Him we live and move and have our being."