Final answer:
All forces are transmitted by carrier particles, and attempts to unify these forces under GUTS suggest a reduction of four fundamental forces to three under certain high-energy conditions.
Step-by-step explanation:
One true statement about all forces is that they are all transmitted by the exchange of a carrier particle. This is a concept that remains consistent across distinct forces such as the electromagnetic, strong nuclear, weak nuclear, and gravitational forces. These carrier particles are virtual particles, meaning they cannot be directly observed during the transmission process.
In physics, the four fundamental forces can be almost entirely reduced to one basic force, known as the electromagnetic force, with gravity being the only force we experience that is not electromagnetic. Advanced research related to Grand Unified Theories (GUTS) suggests that under conditions of incredibly high density and temperature, similar to those in the early universe, forces like the electromagnetic and weak nuclear forces merge into the electroweak force, reducing the four basic forces to three. However, unification, especially involving gravity, proves to be a challenging task due to its unique properties.