The Standard Model of particle physics is the best theory that physicists have to describe both elementary particles and the interactions, or forces that influence them. Srini Rajagopalan: "Everything that you see around you, it's made up of 12 fundamental particles, and the Standard Model describes them, and the forces that govern, the strong, the weak, and the electromagnetic. It still does not accommodate the force we all know, which is gravity." Each of these three forces, or interactions, is associated with a particle or set of particles, which allow that interaction to take place. So the particles and the interactions in the Standard Model cannot be though of as separate, mutually exclusive entities, but are intertwined.