Question

The Carboniferous period belongs to the era:
A. Precambrian
B. Palaeozoic
C. Cenozoic
D. Archaeozoic

Answer 1

Hint: Average global temperatures in the Early Carboniferous Period were high: approximately $20^\circ C$ ($68^\circ F$). During the Middle, Carboniferous cooling reduced average global temperatures to about $12^\circ C$ ($54^\circ F$).

Complete step by step answer:
Let’s discuss the options and find out the correct answer.
- Precambrian: The earliest part of Earth's history is known as the Precambrian which set before the current Phanerozoic Eon. It is named after Cambria, the Latinised name for Wales, where we first studied the rocks from this age. This option is incorrect.
- Paleozoic: A time of dramatic geology is known as the Paleozoic, climatic, and evolutionary change. The Cambrian witnessed is known as the Cambrian explosion, in which most modern phyla first appeared. During the Paleozoic arthropods, mollusks, fish, amphibians, synapsids, and diapsids all are evolved. Though life began in the ocean but eventually transitioned onto land, and by the late Paleozoic, it was dominated by various forms of organisms. It is the correct option.
- Cenozoic: The third of the major eras of Earth's history is known as Cenozoic Era, extending to the present it was beginning about 66 million years ago. This option is incorrect.
- Archaeozoic: Archaeozoic was in between the time 3800 million years to 2500 million years ago and the unicellular organisms are the earliest forms of life. This option is incorrect.
Hence, option B: Palaeozoic is the correct answer.

Note: The Carboniferous period saw the appearance of the first extensive forests on Earth. Atmospheric oxygen levels peaked around $35\%$, compared to $21\%$ today.