Which one of the following era has the longest geological time?a.Cenozoic erab.Mesozoicc.Paleozoic erad.Precambrian era

d. Precambrian era

Explanation:

The Precambrian era is the longest geological time period. It spans from the formation of Earth about 4.6 billion years ago to the start of the Cambrian Period about 541 million years ago. This era covers about 88% of Earth's geological history.

a. Cenozoic era - This is the current and most recent of the three Phanerozoic geological eras, following the Mesozoic Era and covering the period from 66 million years ago to present day.

b. Mesozoic era - This era, also known as the Age of Reptiles or the Age of Dinosaurs, lasted about 180 million years, from about 252 to 66 million years ago.

c. Paleozoic era - This era lasted about 290 million years, from about 541 to 252 million years ago.

d. Precambrian era - This era covers the majority of Earth's geological history, from Earth's formation about 4.6 billion years ago to the start of the Cambrian Period about 541 million years ago.