What can be used to make complicated concepts and systems easier to study and understand?

Models.

Explanation: Models have usually used to simplification the harder subjects, and make it easier to work with.

An example of this is when you do the math for a car moving in the street, where you suppose that the car has an easy shape, like a box, you ignore things like air resistance and such.

Models are used in almost every field of physics, especially in the experimental field, where having a lot of variables is a problem, so the scientist develops models where some of the variables can be ignored, and in this way, the experiment and the math are easier.

the answer is a. the yacht traveled from the dock north to the 200-meter marker in the bay in less than 5 minutes, giving the passengers several more hours to fish.

im doing peak rn so sry if its wrong

its c i just checked it