Final answer:
The correct option is: 2) How does gravity affect the motion of objects? The question that best represents the type of simple and universal questions physicists seek reflects an intention to understand a fundamental aspect of physics applicable in numerous contexts.
Step-by-step explanation:
Physicists attempt to understand the fundamental mechanisms of the universe by asking simple and universal questions. From the given options, question 2, 'How does gravity affect the motion of objects?' best encapsulates the type of question described. This question is broad, applies to many scenarios (hence universal), and seeks to understand a fundamental force that influences every physical object. Question 3 is also about gravity, but it's more specific and does not touch upon the universality of the phenomenon, and questions 1 and 4, while important, do not directly address the motion or the interconnectedness of objects and phenomena.
Physics is successful in part due to its strength in describing the world with simplicity and universality. Issues like the structure of atomic matter and the speed of light are covered within its scope but exploring how gravity—a fundamental force—affects motion is an excellent example of the kinds of questions that lead to deeper understanding and discovery in physics.