Question

Which one of these is a living fossil?

• A. Cycas
• B. Ginkgo
• C. Psilotum
• D. All of the above

Answer 1

The correct option is D All of the above

Option D is correct.
The term 'living fossils' refers to plants or animals that closely resemble any fossil species.
Psilotum of the order Psilotales shows essentially primitive features. While the plants are rootless, the development from the zygote accounts for its primitiveness. The plant body is unspecialized anatomically and the sporophyte is a primitive simple thallus with main axis weakly differentiated into underground rhizome and leafy aerial shoot. The Ginkgoes with their earliest earliest representatives being found in rocks of Permian age some 280 million years old are the earlier line of plants. However, Ginkgo is a tree that is even today grown as an ornamental tree as well as for herbal medicine and is hence considered as the living fossil. Cycas plants which have remained unchanged for the past 300 million years are also called a living fossil.

Therefore, the correct answer is option D.