Q. Which of the following pairs of animal phyla and their key features are correctly matched?

1. Cnidaria – Nematocyst-bearing stinging cells
2. Platyhelminthes – Triploblastic and acoelomate
3. Mollusca – Body segmentation into true metameres

Select the correct option from the codes given below:
Answer: Only 1 & 2
Notes: Cnidarians possess stinging cells called nematocysts. Platyhelminthes are triploblastic, acoelomate flatworms. Molluscs lack true body segmentation into metameres; true segmentation is found in annelids and arthropods. Therefore, only 1 and 2 are correctly matched; 3 is incorrect.