What gas did not appear in any measurable amount until about 2.0 BY BP?

The correct answer is Oxygen.

Explanation:

2.0 BYBP means 2 billion year before present.

The theory of evolution holds that the the synthesis into primitive life forms of the basic chemical components of life such as carbon, nitrogen, hydrogen and oxygen occurred in an atmosphere without any oxygen.

The presence of oxygen in our plant today is explained by two processes.

They are:

The process of Photosynthesis which is the chief contributor of oxygen to the earths atmosphere is said to have spanned billions of years.

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[ answer ]

foliated

[ explanation ]

foliation forms in a rock when pressure squeezes the rock together. the rock then has a design of many different color little lines. there are three types of foliated rock. the types are slate, schist, and gneiss. each type of foliated rock is different based on grain size and foliation characteristics. the lines appear when the rock has been under pressure.

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