Assertion: spiny dogfish's fin | /r/CapableOf | undulate in phase
Facets:
value: actively
type: MANNER
value: with the caudal peduncle
type: MANNER
Source sentences:
text: The movement of the second dorsal fin in phase with the body axis indicates two potential roles for steady swimming in spiny dogfish: (1) the second dorsal fin moves passively with the caudal peduncle; or (2) the second dorsal fin actively undulates in phase with the caudal peduncle.