The description that best explains how inertia affects the effects of gravity on objects in the solar system is:
prevents planets from pulling into one another.
Inertia is the property of an object to resist changes to its state of motion. In the context of celestial bodies, inertia helps maintain the orbits of planets and other objects in the solar system. While gravity exerts an attractive force on these objects, their inertia keeps them moving in a straight line at a constant speed, preventing them from falling directly into the Sun or colliding with one another. This balance between gravitational attraction and inertia is what allows planets to orbit stars rather than spiraling into them.