Single circulation i.e. blood flows through the heart only once during one cycle of passage through the body, is exhibited by

1. Labeo, Chameleon, Salamander

2. Hiipocampus, exocoetus and Anabas

3. Hyla, Rana, Draco

4. Whale, Dolphin, Turtle

The correct option is B

Hiipocampus, exocoetus and Anabas

The correct option is B.

Explanation of the correct option:

• A single circulatory system is present in organisms that possess a two-chambered heart. In the single circulation, blood is passed from hearts to gills. Then after purification, it is passed to the whole body.
• The animals contain two-chambered hearts have one auricle (receiving chamber) and one ventricle (pumping chamber).
• Fishes or member of the Pisces group contains a two-chambered heart and single circulation system.
• Hippocampus, Exocoetus and Anabas are members of the Pisces group, so they show the single circulation.

Explanation of the incorrect options:

Option A:

• In this option, Labeo is a member of the Pisces group, but chameleon salamanders are members of the reptile and amphibia groups, respectively. Amphibian and reptilian members possess a three-chambered heart. Single circulation is not observed in the organisms that possess a three-chambered heart.

Option C:

• In this option, Hyla and Rana belong to class amphibia, and Draco belongs to the reptile class. Amphibian and reptilian members contain three-chambered hearts. Organisms that possess a three-chambered heart do not show a three-chambered heart.

Option D:

• In this option, Whale and dolphin belong to the mammal class and contains a four-chambered heart. Turtle belongs to class reptiles. Single circulation is not shown by the organisms that show 3 and 4 chambered hearts.

Therefore, the single circulation is exhibited by Hippocampus, Exocoetus and Anabas.