>>1
So a real response . . .
Gravity. All things that have mass attract each other. This was very poorly understood until Einstein created a model where anything with mass bends space, basically. This bending of space makes everything go towards things that have mass, so even light, although it has no mass, is bent by strong gravitational fields.
Electromagnetism. Things that are charged create electric fields. Magnetic fields are another form of electric field. Both of these create forces on other charged things. Basically it.
The weak force is the least comprehensible. That doesn't show up often, just in the decays of particles, so it's very small scale. It's really awful, because it doesn't conserve a lot of the things that we thought were always conserved (spin parity, charge parity, lepton number for those who are in the know). Caused by the exchange of a couple of particles.
The strong force is an interaction on the nuclear scale also. This is mostly between quarks, which make up protons and neutrons and some other junk. Quarks are all "red", "blue", or "green." Note that these are not the particles actual colors, that's just a way for us to describe the strange type of charge that they have. All different colors attract. This force holds those particles together.