Final answer:
In Photoshop, you can control various formal elements such as line, shape, color, and texture, as well as principles of composition such as the rule of thirds, level horizon, and filling the frame.
Step-by-step explanation:
In Photoshop, the elements of composition under your control include various formal elements and principles of composition used to create effective and visually appealing images. The formal elements include aspects such as line, shape, color, and texture. These elements can be manipulated to affect the balance, movement, and scale within a composition. Similarly, principles of composition like the rule of thirds, ensuring a level horizon, filling the frame, and avoiding distracting backgrounds can be applied to enhance the overall image. By adjusting these elements and principles, artists can convey specific moods, meanings, or messages in their work.