In which direction does the Y Accelerometer measure motion?

The Y Accelerometer measures motion along the vertical axis. This is essential for applications that require understanding of vertical movement, such as in smartphones for orientation or in gaming devices to track actions like jumping or tilting.

When evaluating how accelerometers work, it's crucial to know that the Y axis typically corresponds to movements that are perpendicular to the ground, which aligns with the up and down motions in a three-dimensional space. Thus, the correct option reflects this standard orientation of how accelerometers are calibrated and used in various devices to track motion effectively.