Banded Iron formations indicate: A- Warm tropical climates B- Ancient glaciations C- An abundance of ozone in marine waters D- The presence of atmospheric oxygen

Which best describes the atmospheric composition befor the banded iron formations? A- poor in free oxygen and rich in ultraviolet rays B- poor in free oxygen and poor in ultraviolet rays C- rich in free oxygen and rich in ultraviolet rays D- rich in free oxygen and poor in ultraviolet rays

How is the ozone layer formed? State its importance for all life forms on earth

The Archean atmosphere could be described as A- oxygen deficient B- oxygen rich C- nitrogen rich D- ozone rich

What is the role of the ozone in the atmosphere?

Which answer best describes what banded iron formation indicate? LO.11 A- Free oxygen in the atmosphere increased B- The PH of earth's oceans was once lower than today C- Iron is a major component of earth's crust D- Chert can only form alongside iron oxide minerals