Question

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

• A. Labeo, Chameleon, Salamander
• B. Hippocampus, Exocoetus, Anabas
• C. Hyla, Rana, Draco
• D. Whale, Dolphin, Turtle

Answer 1

The correct option is B

Hippocampus, Exocoetus, Anabas

The correct option is B.

Explanation of the correct option:

1. A network of blood vessels called the circulatory system transports oxygen and nutrients to the body and removes carbon dioxide and waste products from it.
2. The heart of a fish has the simplest structure of any vertebrate, consisting of two-chambered hearts ( just one atrium and one ventricle). This is called a single circulatory system.
3. In fish, the blood flows straight to the rest of the body after leaving the gill capillaries before returning to the heart.
4. The fish species Hippocampus, Exocoetus, and Anabas have two-chambered hearts.

Explanation of the incorrect options:

Option A:

1. Chameleons are reptiles.
2. Salamanders are a group of amphibians.
3. Blood flow in amphibians and reptiles is controlled by two circuits: the first circulates via the lungs and returns to the heart ( pulmonary circulation), and the second circulates through the remainder of the body's organs, including the brain (systemic circulation).

Option C:

1. Hyla and Rana belong to the class amphibia
2. Draco belongs to the class reptiles.
3. Blood flow in amphibians and reptiles is controlled by two circuits: the first circulates via the lungs and returns to the heart ( pulmonary circulation), and the second circulates through the remainder of the body's organs, including the brain (systemic circulation).

Option D:

1. Whales and dolphins belong to the class mammalian.
2. Turtles belong to the class reptiles.
3. Blood flow in mammals and reptiles is controlled by two circuits: the first circulates via the lungs and returns to the heart ( pulmonary circulation), and the second circulates through the remainder of the body's organs, including the brain (systemic circulation).

Final Answer: Hippocampus, Exocoetus, and Anabas show a single circulatory system.