Question

Hemichordata possesses _____ for respiration.
(A) Lungs
(B) Gill slits
(C) Alveoli
(D) None of the above

Answer 1

Hint: Hemichordata is a phylum of non-chordates with specific similarities with chordates as suggested by its name. They are worm-like organisms that live in burrows and are mainly marine.

Complete answer:
Hemichordates carry out respiration by using gill slits which are present in the pharynx. But along with the gill slits, gaseous exchange occurs over the whole body. The gull slits are in a dorsal position in hemichordates but lateral in chordates. Below is the location of gill slits in hemichordates-

Additional Information:
Hemichordates are marine deuterostome animals and include two main classes- enteropneusta, commonly known as acorn worm, and pterobranchia. Acorn worms are worm-like organisms that live in burrows and are deposit feeders whereas pterobranchs are filter feeders and live in collagenous tubular structures called coenecium.
The body of hemichordates is divided into Proboscis, collar, and trunk as shown in the diagram. They are enterocoelous and possess a complete digestive system and an open type circulatory system with a contractile heart vesicle and two longitudinal vessels. The nervous system is primitive with an intraepidermal nerve plexus.

So, the correct answer is “Gill Slits”.

Note:
Before its general organization, hemichordates were considered as a subphylum under phylum Chordata due to its certain similarities with chordates. But recent scientists like Vander Horse, Marcus, Dawyd, and Hyman gave it the position of a phylum under non chordate.

                                                             Hemichordata