The precambrian time period is the largest on the geological time scale

True!

Explanation:

The longest geologic era was the Precambrian. It began with the formation of the earth about 4.53 billion years ago, and ended about 542 million years ago.

This means this period lasted approximately  3.98 billion years!

As such it's undoubtedly the longest geologic era by a long shot!

True.

Explanation:

The Precambrian period is the largest on the earth's geological scale. It is formed by the Proterozoic, Archean and Hadean eons. It is estimated that this period ended more than 542 million years ago and that it was close to its end that multicellular organisms developed secular division, through a long evolutionary process. As it is the largest division of the earth's geological time, this period covers 90% of the entire geological record on the planet.