Question

Study the following combinations:

Which of the above combinations are correct

• A. I and II
• B. I and III
• C. II and III
• D. III and IV

Hint:

Echinoderm larvae are bilaterally symmetrical, whereas adult echinoderms exhibit radial (pentamerous) symmetry.
This is a classic evolutionary example of retrogressive metamorphosis.

Answer 1

The Correct Option is B

Step 1: Recall the larval stage for each echinoderm class.
Asteroidea larva is Bipinnaria, Ophiuroidea larva is Ophiopluteus, Echinoidea larva is Echinopluteus, Holothuroidea larva is Auricularia, and Crinoidea larva is Vitellaria.
Step 2: Check combination I.
Pairing Asteroidea with Bipinnaria larva and the genus Pentaceros is a textbook correct example, so combination I stands.
Step 3: Eliminate the wrong pairs and confirm combination III.
The combination that wrongly assigns Crinoidea a larval name that actually belongs elsewhere fails, while combination III correctly pairs its class with the right larval stage and representative genus, so it survives the check.
Final answer: Option 2, I and III.