Task: Property Constraint Reasoning (ontology: Sciences/Biology)

The property 'has skeleton' applies to instances of 'organism subdivision', and 'anal region' is a subclass of 'organism subdivision'. Which class can appear as the value of 'has skeleton' for instances of 'anal region'?

A. signalling molecule
B. cell killing
C. organic anionic group
D. material anatomical entity

Answer: material anatomical entity