In Clark's 1960 Research with the Clamworm (Nereis Pelagica), Repeated

Multiple Choice

In Clark's 1960 research with the clamworm (Nereis pelagica) , repeated presentations of a shadow stimulus resulted in a continual decline in the worms' withdrawal escape response. Clark knew that the clamworms had habituated because

A) the clamworms' muscles had become fatigued.
B) the clamworms would still withdraw in response to being prodded.
C) the effects lasted for only a few seconds.
D) the clamworms' sense organs became adapted to the stimulus