Certify Teacher Science Practice Exam 2025 – The Comprehensive All-in-One Guide for Exam Success!

In a planetary system, the force of gravity between two objects is described accurately by the principle that it decreases as the distance between those objects increases. This relationship is governed by Newton's law of universal gravitation, which states that the force of gravity is inversely proportional to the square of the distance between the centers of two masses. This means that as the distance increases, the gravitational force diminishes significantly.

For example, when considering planets and their moons, or the sun and the planets, the gravitational pull that one body exerts on another becomes weaker as they move further apart. This affects the orbits and movements of celestial bodies, illustrating how gravity is a crucial factor in maintaining the structure and dynamics of a planetary system.

The other choices do not correctly reflect the nature of gravitational force in a planetary system. Gravity does not act equally on all components without regard to mass; larger masses exert a stronger gravitational force. Smaller components, such as moons or asteroids, experience weaker gravitational forces relative to larger planets. Lastly, gravity is fundamental in the movement of planets, as it governs their orbits and interactions within a solar system.