Question

Based on the three statements given below, choose the CORRECT option. Statement I: Echinoids have water vascular system.
Statement II: Delthyrium and pedicle foramen are found in the brachial valve of brachiopods.
Statement III: Cardinal teeth, adductor muscles and chondrophore are found in bivalves.

• A. Statements I and III are correct, statement II is incorrect.
• B. Statements II and III are correct, statement I is incorrect.
• C. Statements I and II are correct, statement III is incorrect.
• D. Statements I, II and III are correct.

Hint:

Remember: Pedicle valve = brachiopod pedicle opening; Bivalves = hinge teeth + adductor scars; Echinoderms = water vascular system.

Answer 1

The Correct Option is A

Step 1: Check Statement I.
Echinoids (sea urchins, echinoderms) possess a water vascular system with tube feet, used in locomotion and respiration. Hence, Statement I is correct.

Step 2: Check Statement II.
In brachiopods, the delthyrium (a triangular opening) and pedicle foramen are structures in the pedicle valve, not the brachial valve. Hence, Statement II is incorrect.

Step 3: Check Statement III.
Bivalves are characterized by: - Cardinal teeth (hinge mechanism), - Adductor muscles (close shells), - Chondrophore (internal support for ligament in some bivalves, e.g., Mactridae). Thus, Statement III is correct.

Step 4: Combine results.
Only Statements I and III are correct; Statement II is incorrect.

Final Answer:
\[ \boxed{\text{(A) Statements I and III are correct, statement II is incorrect.}} \]