19. Single circulation i.e., blood flows through the heart only once during one cycle of passage through the body, is exhibited by
19. 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

The answer is (b) Hippocampus, Exocoetus, Anabas

Explanation: Option a) Chameleons are reptiles, while Salamanders are amphibians, both of which have three chambered hearts and partly double circulation. All of the Amphibians in Option c) have partial double circulation. Option d) is incorrect because a whale is a mammal, but a turtle is a reptile.