Question

identify the blue structure. auricle gastrovascular cavity eyespot pharynx

Explanation:

In flat - worms like the one shown, the auricle is a sensory structure located on the sides of the head region. The gastrovascular cavity is the main cavity for digestion and circulation. The eyespot is a light - sensitive structure. The pharynx is used for feeding and can be extended out of the body. Without seeing the blue - colored part, but based on general knowledge of flat - worm anatomy, if it's a side structure, it could be the auricle.

Answer:

A. Auricle