What are Layers in Unity primarily used for?

Layers in Unity are primarily used to categorize GameObjects for rendering and collision purposes. Using layers allows developers to organize GameObjects in a way that simplifies the management of their interactions within the game. For instance, when it comes to rendering, layers can determine what objects are visible to the camera. This can help optimize performance by culling objects that do not need to be rendered.

Additionally, layers play a crucial role in collision detection. They allow developers to specify which layers can interact with each other. For example, you might want certain objects to collide while preventing others from doing so. By carefully managing layers, developers can streamline both the rendering process and the physics calculations involved in collision detection, resulting in more efficient gameplay.

Other choices, while related to key aspects of game design, do not accurately represent the primary function of layers in Unity. Graphics quality, character behavior in animations, and audio management pertain to different elements of game development rather than the use of layers.