AP BIOLOGY

Detailed explanation-1: -Planarians are photophobic and when exposed to light they seek cover [21]–[23]. This negative phototaxis has been used to evaluate regeneration of the visual system [23]–[26], as well as memory storage and transference [27], [28].

Detailed explanation-2: -Does the planaria move toward or away from the light? Planaria exhibits negative phototaxis, moves away from the light.

Detailed explanation-3: -Planarians sense visible light through their cerebral eye. On the other hand, UV light sensing (extraocular) is dispersed throughout the planarian body. In a competition experiment, the aversive response through the cerebral eye appears to be dominant.

Detailed explanation-4: -The two eyes in planarians are made up of only pigment cells and photoreceptor cells, and it is these photoreceptor cells that respond to light, although there are a number genes that seem to be responsible for this negative phototaxis.