Final answer:
Rotifers use their crown of cilia for locomotion by moving the cilia to create currents that propel them through the water, and for feeding by utilizing these currents to direct food towards their mouth where it is then processed by the mastax.
Step-by-step explanation:
Rotifers, which are microscopic multicellular organisms mostly found in aquatic environments, use their cilia-adorned corona chiefly for two purposes: locomotion and feeding. The crown of cilia, looking like a rotating wheel under a microscope, creates currents that pull water and food particles towards the rotifer’s mouth. While in motion, these cilia act like oars to propel the rotifer through the water.
For feeding, the movement of the ciliated corona directs food into the rotifer's mouth, where it encounters the mastax, a unique jaw-like structure that grinds the food before it moves into the digestive system. The process of gathering and ingesting food is called filter feeding, and rotifers serve an important role in aquatic food webs by consuming dead material, algae, and other microscopic organisms. Essential for their survival, the ciliated corona is therefore a multipurpose structure vital to both the locomotion and feeding mechanisms of rotifers.