Which feature allows for efficient automation of volume changes in a mix?

The feature that allows for efficient automation of volume changes in a mix is real-time automation. This function enables users to adjust volume levels and other parameters dynamically while the track is playing. With real-time automation, you can record your adjustments on-the-fly, allowing for precise control over volume changes that reflect the nuances of the performance.

During playback, real-time automation captures the movements of the fader as you manipulate it, which can then be edited or fine-tuned in the automation lanes afterward. This method is particularly beneficial for intricate mixes, where different elements may require varying volume levels throughout the track.

In contrast, other options serve different purposes. Track Freeze is designed to conserve CPU resources by rendering the effects and processing of a track temporarily, preventing further changes. Write Automation allows for recording automation but does not offer the same flexibility as real-time adjustments, as it writes over existing automation. Clip Gain is useful for adjusting the gain of individual clips but does not provide the same level of detail for automation throughout an entire track as real-time automation does.