question_answer 53)

    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:

                  (b) The examples and the relation of animal group and heart are as

Animal Group	Heart	Examples
Fishes	2-chambered heart (one atrium and one ventricle) single circulation	Labeo, Hippocampus, Exocoetw, Anabas, etc. Fishes.
Amphibians and Reptiles	3-chambered heart (two atria and one ventricle) mixing of oxygenated and deoxygenated blood.	Salamander, Hyla, Rana (Amphibians) Chameleon, Draco, Turtle (Reptiles)
Brids and Mammals	4-chambered heart (two atria and two ventricle) No mixing of blood	Pigeon, parrot (birds), whale, dolphins, humans (Mammals)

  According to this chart 2 chambered heat is present only in fishes and blood flues only once during are cycle. Group (b)-contain fishes so correct answers in option ?b?.