Question

Mesozoic era was dominated by
A. Birds
B. Fishes
C. Reptiles
D. Mammals

Answer 1

Hint: The evolutionary history explaining the evolution of different living forms are quite vast. The developmental history of different organisms from the simplest to the most complex one, shows the successive changes which occurred through several generations in the biological population. The history of developments of living organisms are represented in three important eras which are the Palaeozoic era, Mesozoic era and Coenozoic era.

Complete answer:
The living organism arises from the simplest types of cells. With due course of time, a great amount of changes occurred in the environment. Due to these changes, various types of different changes also occurred in the living organism. The important changes brought about the development of different species of animals and plants as well as several other species were removed and became extinct. The different types of species accumulated the changes and it gave rise to the present day species of organisms.
The Mesozoic era is one of the major eras of the three geological eras. The other two important eras are the Palaeozoic era and the Coenozoic era. The Palaeozoic era started earlier and was followed by the Mesozoic era. The Mesozoic era is considered as the time interval between two fifty two million years and extending to sixty-six million years. It is also known as the age of the conifers or the age of the reptiles.
The Mesozoic era is considered as the middle and connecting era between the old or ancient era and the modern or new era. The Mesozoic era is divided into three major periods which are the Triassic, Jurassic and the Cretaceous period.
The environment of the Mesozoic era was hotter than present day and the climate varied between hot and cold climates. This era showed the rise of the dinosaurs. They first appeared during the Mid-Triassic era and were the dominant vertebrates that lived on the land. The animal life was dominated by different species of dinosaurs such as pterosaurs, mosasaurs and several other aquatic reptiles also developed in this era. Due to further changes, the first bird also radiated from the dinosaurs in this period. The Mesozoic era showed the growth of the conifers or the gymnosperms. The gymnosperms were the dominant plants of this period and later on the angiosperms came into existence. However, though the dinosaurs survived and developed in this era, towards the end of the Cretaceous period there occurred mass extinction of the species of dinosaurs. The Mesozoic era is known as the era of the dinosaurs due to the rise and subsequently the extinction of the dinosaurs.

Therefore, the option C is the correct and appropriate option.

Note:
The Mesozoic era followed the Palaeozoic era. During the Mesozoic era, the reptiles, especially the dinosaurs were the important and ruling land vertebrates. They dominated the Mesozoic era. Different species of dinosaurs existed and flourished during this period and the first bird arose from the dinosaurs. Towards the end of the Cretaceous period, the dinosaurs faced mass extinction.