It seems like you're asking about the fundamental forces of nature. These are not "things" that occur, but rather the interactions that govern the behavior of matter and energy in the universe.

Here's a breakdown of the four fundamental forces:

1. Strong Nuclear Force: The strongest force, responsible for holding the nucleus of an atom together. It acts over incredibly short distances, only within the nucleus.

2. Electromagnetic Force: This force governs the interactions between charged particles, like electrons and protons. It's responsible for electricity, magnetism, and light. It's weaker than the strong force but has a longer range.

3. Weak Nuclear Force: Responsible for radioactive decay. It's weaker than the electromagnetic force and acts over even shorter distances than the strong force.

4. Gravitational Force: The weakest but longest-range force, responsible for the attraction between any two objects with mass. It governs the motion of planets, stars, and galaxies.

Let's emphasize:

* Forces aren't "things": They are the ways in which matter and energy interact.

* Forces are always present: They're not just "occurrences," they're always acting, even if we don't notice them.

* Forces can be combined: Many natural phenomena involve the interplay of multiple forces.

If you have more questions about specific forces or their effects, feel free to ask!