Question

An example of class Polychaeta is
A. Nereis
B. Pheretima
C. Hirudinaria
D. All of the above

Answer 1

Hint: Annelid worms include the class of polychaeta. It is the class of bristle worms. They are found mainly at the depths of oceans. Polychaeta includes Nereus (genus of polychaete)that are found at the challenger deep of the sea. Pheretima and hirudinaria come in the class Clitellata. Nereididae are the family of polychaete worms.

Formula used: About 8,000 living species of polychaete are known till now they include rag worms, lugworms, bloodworms, sea mice, and others, are marine worms that have segmented bodies. They bear parapodia with setae, or tiny bristles. Size of polychaetes varies from a few millimeters to about 3 m (10 feet).
Neries is the genus of polychaete of the family Nereidae. They have a pair of leg-like protrusions in every segment. This type of protrusion is called parapodia. Many bristles are present on the parapodia which are called chaetae. Chitin is the main component of chaetae. These parapodia structures are used for the purpose of locomotion.
Pheretima is the genus of the family Megascolecidae of class Clitellata. These are the earthworms mostly found in parts of Southeast Asia. They have glandular tissue present on segments. They are hermaphroditic and reproduction can be either sexual or parthenogenetic. They are used as medicine in china.
Hirudinaria is a common leach found in freshwater tanks, ponds and lakes. Class Clitellata involves Order Hirudinida and species H. medicinalis.
From the above information we can conclude that Nereis is the example of polychaeta.
So, the correct answer is option A.

Note: In polychaete sexes are usually separate but some of the polychaete species both sexes are present in the one individual. They are hermaphrodites. They play an important role in turning over bottom sediments in the sea. Nereidae includes about 500 mostly marine animals which are grouped into 42 genera.