Question

Spiny bodied animals
(a) Are exclusively marine
(b) Have ventral anus
(c) Have radially symmetrical larva
(d) Lack excretory system
Which of the statements are correct?

• A. All correct
• B. a & b
• C. a, c, d
• D. only a

Answer 1

The correct option is B a & b

Echinoderms are also called as spiny bodied animals. (Echinos: spiny, derma: skin).
These animals show following characteristics:

1. These are exclusively marine
2. Grade of organization: organ system grade
3. Germ layer: triploblastic
4. Symmetry: Adults are radially symmetrical while the larvae are bilaterally symmetrical
5. The shape of the body is flat, star-like, spherical or elongated.
6. Presence of water vascular system
7. Mouth is present on the ventral side while anus is present on the dorsal side.
8. Presence of water vascular system

Few examples of echinoderms are starfish, sea urchin, sea lily, cucumaria (sea cucumber), Antedon etc.