There has been an increase in the number of chambers in heart during evolution of vertebrates. Give the names of the class of vertebrates having two, three or four-chambered heart.

Which one of the following sets of animals share a four chambered heart?

Name the main as well as accessory chambers of heart of frog.

Differentiate the following on the basis of characters asked in the subparts: Crocodile/Toad(number of chambers of heart)

Choose the correct alternative: Earthworm has two/four paris of lateral hearts.

These questions consist of two statement each, printed as Assertion and Reason. While answering these questions, you are required to choose any one of the following four responses. A. If both Assertion and Reason are true and Reason is a correct explanation of the Assertion. B. If both Assertion and Reason are true but Reason is not a correct explanation of the Assertion. C. If Assertion is true but Reason is false. D. If both Assertion and Reason are false. Assertion: Bats and whales are classified as mammals. Reason: Bats and whales have four-chambered heart.

The population of a certain is known to increase at a rate proportional to the number of people presently living in the country. If after two years the population has doubled, and after three years the population is 20,000 estimates the number of people initially living in the country.

For a set of five true or false questions, no student has written all correct answers, and no two students have given the same sequence of answers. What is the maximum number of students in the class, for this to be possible ?