They determine the interactions between all known quarks and leptons. If no other particles exist and the quarks and leptons have no sub structure, then thissingle TOE will fully describe the behaviour of groups of these particles, and in principle the most complex systems that are made up by them. The modern day phyicist will probably raise his shoulders and wonder where you worry about. Here is where Philosophy and Religion comes in to ask for more. You will arrive at the place you started if you keep travelling in the same direction.
Space is curved.
Finite without boundaries. But curved in a fourth dimension that we cannot be aware of. We have no kowledge of any space dimension beyond the three we are familiar with. If the sphere gets bigger, the inhabitants see distances grow and wonder what's behind the farthest galaxies. Distances are not just increasing in their two- dimensional space, space itself is expanding.