Answer question numbers (a) - (d) on the basis of your understanding of the following paragraph and the related studied concepts :
The separation of the right side and the left side of the heart is useful to keep oxygenated and de-oxygenated blook from mixing. Such separation alllows a highly efficient supply of oxygen to the body. This is useful in animals that have high energy needs, such as birds and mammals, which constantly use energy to maintain their body temperature. In animals that do not use energy for this purpose, the body temperature depends on the temperature in the environment . Such animals, like amphibians or many reptiles have three- chambrered hearts, and tolerate some mixing of the oxygenated and de-oxygenated blood streams. Fishes, on the other hand, have only two chambers to their hearts, and the blood is pumped to the gills, is oxygenated there, and passes directly to the rest of the body.
(a) What does the give diagram depict ?
(b) In which type of organisms would you find this type of transportation ?
(c) Explain why some animals like fishes have only two chambered heart ?
(d) From this study what can you deduct about evolution ?

Explanation

(a) The given diagram depicts transportation and exchange of respiratory geses i.e. `O_(2) and CO_(2)` from the heart to various body parts, including lungs.
(b) This is showing double circulation, which is seen in warm blooded animals.
(c) Fishes have only two chambered heart where the oxygenated and de-oxygenated blood gets mixed up. It is this mixed blood which is transported through the body. This is known as single circulation.
(d) From evolutionary point of view it show that as animals evolved, they came to posses a pump for circulating theri blood to different parts. This pump like organ i.e., heart initially could not segregate oxygenated and de-oxygenated blood and hence such animals could not regulate their dody temperature while it became 3 and then 4 chambered where the animals could regulate their body temperature, due to higher availability of energy.