A diagram in the course handout shows that a rotifer has a body cavity derived from blastocoel and not fully lined by mesoderm. Identify the related structure or process.

Correct Answer: C

pseudocoelom

Rotifers are pseudocoelomate animals. Their pseudocoelom provides internal space and support but is not a true coelom completely lined by mesoderm. This MCQ belongs to the Rotifera topic in Animal Diversity-I and is written to test concept understanding rather than memorized wording.