Which statements describe geologic gaps? Check all that apply

Scientists developed the geologic time scale as they studied rock layers and index fossils.

Precambrian time makes up 88 percent of Earth’s history.

The first birds appeared during the Jurassic period.

Humans appeared during the Cenozoic era.

Explanation:

edgeunity 2021

straight or amphibians are homeothermic to thermal

oxygen = 21% of the atmosphere

nitrogen = 78%

carbon dioxide = 0.1%

argon =0.934%