In a specimen-based viva, the examiner describes this case: a dissected mollusc shows the digestive, reproductive, and excretory organs concentrated in one body region. Choose the concept that fits it best.

Correct Answer: B

visceral mass

The visceral mass contains most internal organs of a mollusc. Together with the mantle and foot, it forms part of the typical molluscan body plan. This MCQ belongs to the Mollusca topic in Animal Diversity-I and is written to test concept understanding rather than memorized wording.