Answer: Pseudocoelomates have a body cavity that is not lined by mesoderm.
- A Pseudocoelomates have no body cavity
- B Pseudocoelomates have a body cavity that is not lined by mesoderm
- C Pseudocoelomates have a body cavity lined largely by mesoderm
- D There is no difference, the terms are interchangeable
Correct answer: B. Pseudocoelomates have a body cavity that is not lined by mesoderm
Explanation: In pseudocoelomates such as Nematoda, the body cavity is not lined by mesoderm on both sides; in true coelomates, the body cavity is completely lined by mesoderm.
Moving across the animal phyla, body organisation becomes progressively more complex: from no symmetry and cellular organisation (Porifera) through radial/diploblastic (Cnidaria), bilateral/acoelomate (Platyhelminthes), pseudocoelomate (Nematoda), to a true coelom with full organ systems (Annelida and beyond).
Concept context
Phylum-level classification of the animal kingdom from Porifera to Chordata, based on body symmetry, coelom, and segmentation. One of the most example-heavy chapters for NEET.