Question

Which of the following has a 3 chambered heart?
A. Salamander
B. Fish
C. Crocodile
D. Dolphin

Answer 1

Amphibians have a 3-chambered heart. They have 2 atria and one ventricle. It is taken care to mix the oxygenated and deoxygenated at the least level. This forms the incomplete double circulatory system. They do not require a very complex system.

Complete answer:
In this wide diversity of organisms, they are organized into various phylum to make their study easier. There are specific features to the members belonging to a group. Vertebrates have the heart to pump blood throughout the body.

So let us see the animals to which group they belong.

Option A. Salamander – It belongs to the amphibian group that can stay both on land and in water. Being an amphibian it has a lower level of the circulatory system and hence a 3 chambered heart.

Option B. Fish- It has 2 chambered hearts as blood leaved gills immediately to be circulated in the body. They do not need such a complex system.

Option C. Crocodile- it belongs to the reptilian group. Though reptiles have 3 chambered hearts, the crocodile is the only exception. It has a 4 chambered heart.

Option D. Dolphin- It is a mammal so like us they too have a 4 chambered heart with 2 auricles and 2 ventricles.

So the answer is option A: Salamander

Note: Mammals have a hairy body and reptiles have scales. Mammals provide milk to their younger ones but reptiles lay eggs. Reptiles grow throughout their life and shred teeth. They are mostly cold-blooded whereas most mammals are warm-blooded. They are believed to have evolved 300 million years ago.