What is described as the space between the vocal folds when they are open?

The glottis is the correct term used to describe the space between the vocal folds when they are open. It plays a crucial role in the production of sound as air flows through this opening during phonation. When the vocal folds are apart, the glottis allows air to move freely, which is essential for breathing and vocalization.

The other choices refer to different anatomical structures associated with the respiratory and vocal systems. The epiglottis is a flap of tissue that acts as a valve, directing food away from the windpipe during swallowing; the trachea is the windpipe that connects the larynx to the bronchi, conducting air to and from the lungs; and the bronchi branch off from the trachea and lead into the lungs. Each of these structures plays distinct roles in the respiratory system, but they do not refer specifically to the space between the vocal folds.