Wastewater New York State Practice Exam

What is a characteristic of Rotifers?

1. They are single-celled organisms

2. They have a rotating cilia on the head

3. They do not consume bacteria

4. They only exist in freshwater

The correct answer is: They have a rotating cilia on the head

Rotifers are characterized by the presence of a unique structure known as the corona, which is comprised of cilia arranged in a rotating pattern atop their heads. This characteristic allows them to create currents in the water, aiding in food capture and locomotion. The rotation of the cilia is a distinctive feature that facilitates feeding on microscopic particles, primarily algae and bacteria. The other options contain inaccuracies regarding the nature and habitat of rotifers. While many species of rotifers are found in freshwater environments, they are also present in marine and even semi-terrestrial habitats. They are not single-celled organisms; rather, they are multicellular microscopic animals. Furthermore, rotifers do consume bacteria as part of their diet, contributing significantly to microbial food webs.