Question

Ascaris is characterized by

• A. Absence of true coelom but presence of metamerism.
• B. Presence of neither true coelom nor metamerism.
• C. Presence of true coelom and metamerism.
• D. Presence of true coelom but the absence of metamerism.

Answer 1

Answer: (B)

The body of Ascaris is elongated, cylindrical gradually tapering at both ends. There is no metameric segmentation. In Ascaris, between the body wall and visceral organs is a spacious fluid-filled cavity. They belong to the phylum Aschelminthes that have pseudocoelom as their body cavity.
Segmentation, also called metamerism, or metameric segmentation, in zoology, the condition of being constructed of a linear series of repeating parts, each being a metamere (body segment, or somite) and each being formed in sequence in the embryo, from anterior to posterior. E.g., animals of phylum Annelida.