On the workbook page there are objects with body parts next to them: an eye, nose, mouth, ear and hand. The exercise is to circle the body part that represents the primary sense for interacting with the object. So we smell flowers, and taste cupcakes.
Clover circled the hand next to the rainbow.
maiki: What do you do with a rainbow?
Clover: You touch it.
m: How do you touch a rainbow?
C: With your hand.
Duh.