Which is the filter feeder?
A)Amoeba
B)Leech
C)Spider
D)Paramecium

Hint: Filter feeders are classified as a sub-group of suspension feeders called animas. By straining suspended matter and food particles from water, they are known to eat, usually by running the water over a specialized filtering structure.

Complete answer:
Other species include clams, krill, sponges, baleen whales, and many fish that use fiter feeding as a form of feeding (including some sharks). Few birds are also filter feeders, such as flamingos and certain kinds of duck. In clarifying water, filter feeders may play an important role and are thus known to be ecosystem engineers. In bioaccumulation and, as a consequence, as indicator species, they are also important. Paramecium is referred to as a filter feeder because it uses cilia to channel food through an oral groove where cilia extracts unnecessary particles. Food enters the cytostome in the food vacuole and it is digested.

Each food vacuole is composed of food particles and along with cyclosis it undergoes circulation in a particular direction. With the aid of such enzymes secreted from protoplasm into the vacuoles, digestion takes place. First, the substance of the vacuole becomes acidic and then alkaline. During the alkaline stage, the main digestion of food happens. Proteins are converted into amino acids and carbohydrates into soluble sugar and glycogen in the digestive phase.

Hence, the correct answer is option (D)

Note: Many active suspension feeders are sometimes referred to as 'filter feeders' because they pump water through a filter structure that extracts particles from the suspension suspension (e.g., sea squirts, certain worms that secrete mucus nets, and baleen whales).