Question

The most distinctive feature of which of the following Phylum is the presence of water vascular system?
1. Echinodermata
2. Hemichordata
3. Mollusca
4. Ctenophora

Answer 1

Correct Answer - Option 1 : Echinodermata

The correct answer is Echinodermata.

• Body surface of the members of Phylum Echinodermata is rough, covered with spines or spicules. 

• They are the most common and widely distributed marine animals.
• The symmetry of the body is oriented along five radii i.e pentaradial.
• The digestive system is complete with the mouth on the ventral side and anus on the dorsal side.
• The most distinctive feature of echinoderms is the presence of a water vascular system which helps in the locomotion, capture and transport of food and respiration.
• An excretory system is absent and Reproduction is by sexual means.
• Fertilisation is usually external and the development is indirect with free-swimming larva.
• Common Examples are- Asterias (Star fish), Echinus (Sea urchin), Cucumaria (Sea cucumber).