Which of the following is unique to the molluscs and has no equivalent in any other animal?
| 1. | Haemocoel | 2. | Hemocyanin |
| 3. | Radula | 4. | Metamerism |
| 1. | It is the second largest animal Phylum after Phylum Arthropoda. |
| 2. | It includes animals that are bilaterally symmetrical, triploblastic, and coelomate. |
| 3. | Body is covered with a calcareous shell and is metamerically segmented with a distinct head, muscular foot, and visceral hump. |
| 4. | Gills are present in the mantle cavity, a space between the mantle and the hump. |
| 1. | Pinctada | Pearl Oyster |
| 2. | Aplysia | Sea hare |
| 3. | Dentalium | Tusk shell |
| 4. | Loligo | Devil fish |