Throughout the period, which began about 2.6 million years ago and extends to the present, ice sheets formed, advanced over broad areas, and then wasted away.

Quaternary period

Explanation:

Throughout the quaternary period, which began about 2.6 million years ago and extends to the present, ice sheets formed, advanced over broad areas, and then wasted away.

The quaternary period is a geological time period that began 2.6 million years ago and encompass the present time. This time period is divided into two; the Pleistocene Epoch, which lasted from approximately 2 million years ago to about 12,000 years ago, and the Holocene Epoch, which began about 12,000 years ago. This period is referred to as the ice age due to formation of ice sheets during this period, some of the ice sheets became glaciers. These accumulated ice sheet wasted away when the earths atmospheric temperature increased.

all three options are correct