Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A): Aschelminthes are classified as true coelomates. Reason (R): In Aschelminthes, the body cavity is not lined by mesoderm; instead, the mesoderm is present as scattered pouches between the ectoderm and endoderm. In the light of the above statements, choose the most appropriate answer from the options

Step-by-step solution

Assertion (A) is incorrect. Aschelminthes are not true coelomates; they are classified as pseudocoelomates. Reason (R) is correct. The defining feature of a pseudocoelom is that the body cavity is not lined by mesoderm. Instead, the mesoderm is present as scattered pouches between the ectoderm and endoderm. Because Aschelminthes possess this exact structural arrangement, they are termed pseudocoelomates. Therefore, Assertion is incorrect but Reason is correct. Answer: Assertion is incorrect but Reason is correct.