Question

Identify the pairs that are correctly matched.

(i)	Crocodile	Four chambered heart
(ii)	Sea urchin	Parapodia
(iii)	Obelia	Metagenesis
(iv)	Chondrichthyes	Placoid scales

• A. (i), (iii) and (iv)
• B. (ii), (iii) and (iv)
• C. (i) and (iv)
• D. (i) and (ii)

Answer 1

The correct option is A (i), (iii) and (iv)

Reptiles generally have a three chambered heart, except a few groups such as crocodiles, which have a four chambered heart. Sea urchin is an echinoderm, and does not have parapodia. Parapodia are locomotory organs found in invertebrates such as annelids (e.g., Nereis). Obelia is a cnidarian that exhibits metagenesis, which is an alternation of generations between an asexual polypoid stage and a sexual medusoid stage. Chondrichthyes is the taxonomic class that includes cartilaginous fishes such as shark. They typically have their skin covered with placoid scales.