Question

Cephalopoda is characterised by
A. Coming together of head and foot
B. Enlargement of tentacles
C. Presence of siphon
D. All the above

Answer 1

Desert plants are highly adapted to live in areas where water is not readily available. They have a waxy covering called cuticle on the epidermis that prevents the loss of water through transpiration.

Complete answer:
Molluscs constitute the second largest animal phylum. Molluscs are land or marine organisms with an organ-system level of organisation. The body is enclosed by a calcareous shell and has a distinct head, a muscular foot and a visceral hump.

All cephalopods have the same basic anatomy. The cephalopods are soft-bodied, having arms around the mouth; highly formed, image-forming eyes; and a tube-shaped organ called a funnel or a siphon near the head. The funnel, or siphon, is a muscular structure found on the ventral surface of the mantle. It has many roles, including respiration and waste disposal. They have a rigid casing called a mantle that covers and protects their organs. They all have arms attached directly to their heads, although some species have tentacles. The arms have cirri, suckers or hooks on their undersides.

The cephalopods have three hearts, two of which transfer blood to the gills and the other pump blood to the rest of the body. Their brains are much larger than those of other invertebrates, and most animals are capable of learning and retaining knowledge. They have two eyes that are commonly described as highly complex.

Thus, the correct answer is option D i.e., All the above.

Note: Cephalopods have developed a closed circulatory system that does not rely on the distribution of blood to tissues in the body. They have a closed circulatory system so that they can move much faster.