Or the difference command to work, what needs to happen? a. the image needs to contain at least three colors. b. the image needs to include text. c. the objects need to be moved to the same layer. d. two overlapping objects need to be selected.

D. Two overlapping objects need to be selected.

Explanation:

    You can combine vector objects to create shapes in a variety of ways in Illustrator. The resulting paths or shapes differ depending on the method used to combine the objects.

Pathfinder effects

Pathfinder effects allow you to combine multiple objects using interaction modes. When you use Pathfinder effects, you cannot edit interactions between objects.

Composite shapes

Composite shapes let you combine multiple objects and specify how you want each object to interact with the others. These shapes are more versatile than compound paths, as they offer four types of interactions: addition, subtraction, intersection and exclusion. In addition, the underlying objects are not changed so that you can select each object in a composite form to edit it or change its mode of interaction.

the answer is counterpoint.

counterpoint definition: "the art or technique of playing a melody or melodies in conjunction with another, according to fixed rules."

counterpoint is present in a lot of baroque music- such as bach (notably his wtc prelude and fugues) and scarlatti, but can also be found in music by mozart, beethoven. it can even be found in music as modern as john williams!