Which property is relevant when discussing planetary models like the Solar System?

The relevance of the first option lies in the concept of gravitational dominance in planetary models, such as the Solar System. In these systems, a central body—like the Sun—has a significantly larger mass compared to the planets and other objects orbiting it. This substantial mass leads to a strong gravitational force, which pulls these smaller components towards it.

This gravitational pull is what maintains the orbits of planets, moons, and other celestial bodies. The interaction creates a stable system where the massive body dictates the motion of the smaller bodies, keeping them in their respective orbits. This principle is fundamental in understanding celestial mechanics and the dynamics of solar systems in general.

In contrast, the other options do not accurately describe the interactions and relationships between celestial bodies. The idea that all components have equal mass and influence each other's movement equally doesn't hold in planetary systems where the mass disparity is significant. Furthermore, the notion that components are independent of one another disregards the gravitational interactions that bind them together in a coherent system. Lastly, stating that forces acting on the components are always equal overlooks the fact that in a gravitational system, forces vary in strength based on mass differences and distances, resulting in a dominant gravitational force from the more massive body.