Question

Which of the following is a living fossil?
(A) Coelacanth
(B) Limulus
(C) Sphenodon
(D) All of the above

Answer 1

Hint:The living fossil is defined as the organisms that are known from the similar characters of the other species or it is known only from the fossil record. They originated from very long years back. These organisms survive but its close relatives resemble its characteristics and are extinct.

Complete answer:
The Coelacanth latimeria is viewed as a living fossil, since it is accepted to be the sole living individual from its taxon in any case or it is only known from fossils, with no nearby relations alive and to have developed into generally its present structure roughly million years back. Horseshoe crab which is also known as Limulus which are marine arthropods of the family Limulidae and order xiphosura.

They live basically in and around shallow sea waters on delicate sandy or sloppy bottoms. They have originated before 450 million years back, and hence horseshoe crabs are viewed as living fossils. Tuatara or Sphenodon have been considered as the living fossils as they hold numerous basic characteristics from around the squamate rhynchocephalia. Hence all the options given are correct.

Thus the correct answer is option (D)

Note:The entire body of the horseshoe crab is covered by the very hard layer. They possess the two compound eyes. The females of this horseshoe crab is slightly larger than male and the reproduction most probably happens in the shallow water areas.