Which axis controls the depth of your 3D layer in Adobe After Effects?

The z-axis is the correct choice because it represents depth in a 3D space within Adobe After Effects. In a typical 3D coordinate system, the x-axis and y-axis correspond to horizontal and vertical movements, respectively. The x-axis typically controls left and right positioning, while the y-axis influences up and down positioning. The z-axis, however, is crucial for controlling how far forward or backward a layer is positioned in relation to the camera, allowing for depth manipulation. This makes it essential for creating and managing three-dimensional scenes in After Effects. The w-axis does not exist in a standard 3D space context, making it irrelevant for this particular question.