Question

Starfish does not possess a specialized____________.

• A. Mouth
• B. Anus
• C. Head
• D. Arms

Answer 1

Answer: (C)

Head

Asterias is commonly known by the name of starfish.

Asterias has a radially symmetrical and pentamerous body.

The body consists of a central, pentagonal central disc from which radiate out five elongated, tapering, symmetrical spaced projections, the rays or arms. The lower surface is flat, less pigmented and is called the oral or actinal surface.

The oral and aboral surfaces are not the ventral and dorsal surfaces but correspond to the left and right sides of the bilaterally symmetrical larva.

The axes occupied by the arms are known as radii and the regions of the central disc between the arms are inter-radii. A well defined head is entirely absent.

So, the correct answer is 'Head'.