Flippers of Penguins and Dolphins are examples of:

Which of the following pairs represents analogous organs?

In $1938$,a fish caught in .......... was thought to be extinct,but it was a Coelacanth.

Most primitive living mammals,which provide evidence of organic evolution from geographical distribution,are found in:

Which one of the following is not a vestigial organ in humans?

In the developmental history of the mammalian heart,it is observed that it passes through a two-chambered fish-like heart,a three-chambered frog-like heart,and finally a four-chambered stage. To which hypothesis can this above-cited statement be approximated?