Question

Which of the following is a characteristic feature of fishes?

• A. Tail and four-chambered heart
• B. Two-chambered heart and gills
• C. Four-chambered heart and scales
• D. Scales and lungs

Answer 1

The correct option is B

Two-chambered heart and gills

• Fishes have a two-chambered heart - one atrium and one ventricle.
• It circulates only deoxygenated blood, received from the veins. The heart in fishes is thus a 'venous heart'.
• Gaseous exchange in fishes occurs through the respiratory organs, gills.
• Hence a two-chambered heart and gills are characteristic features of fishes.

So, the correct answer is option B.