Question

Modern birds rose in
A. Palaeozoic
B. Cenozoic
C. Mesozoic
D. Archaeozoic

Answer 1

It includes three eons; the Hadean, Archean, and Proterozoic. Proterozoic is subdivided into six geologic periods. Modern birds rode in the era when dinosaurs were dominating the earth.

Complete step by step answer: The Mesozoic era lasted more than 180 million years. During this time, many modern forms of plants, invertebrates, aves and fishes evolved. In this era, the land was occupied by dinosaurs which were the dominant animals, while the oceans were populated by large marine reptiles, and Pterosaurs ruled the air. Modern birds arose in this era. This era includes 3 well known periods called the Triassic, Jurassic and Cretaceous periods.
i. In the Paleozoic era, the cycads, primitive conifer and ferns were started to spread across the landscape. 244 million years ago Permian went extinct which devastated the marine biota like tabulate and rugose corals, and most crinoids died out, as did the last of the trilobites.
ii. In the Cenozoic era the cave lions, sabre-toothed cats, cave bears, giant deer, mammoths, and so many organism’s species were prevailing. Almost all the plants living today had its roots in the Cenozoic era. Also during this time, the Earth's crust cooled enough that rocks and continental plates began to form. In the early stages of the Archean, life first appeared on Earth which is proved by the archaeologists who found fossils which date to nearly 3.5 billion years ago and it consists of bacteria microfossils.
Hence, the correct answer is option C.

Note: The geological history includes three eons namely the Hadean, Archean, and Proterozoic. In the Hadean era, the large disc was formed around the sun from the cloud of gases and dust, and it was called an accretion disc. From this accretion disc, the planet named Earth was formed, nearly 4,500 million years ago. The Archean eon dates to nearly 4,000 to 2,500 million years ago. During this time, the Earth's crust cooled and the rocks and continental plates began to form. The Paleozoic spanned from roughly 542 to 251 million years ago.