Plz help i think it's a letter but i'm not sure

As our current atmosphere formed, the concentrations of various atmospheric gases fluctuated. match each gas with the explanation that best describes how its proportion changed during the evolution of the atmosphere.

What problem does obeng say that we have in the 21st century? 2. obeng argues that the pace of change has eclipsed the pace of learning. do you agree or disagree? why? 3. what is "smart failure" according to obeng?

How did shays' rebellion reveal the need for a revision of the articles of confederation? a) shays' rebellion exposed the weakness of the central government as written in the articles of confederation. b) shays' rebellion strengthened the ideas of the anti-federalists in the need for a strong national government. c) shays' rebellion illustrated the need for organized local government factions to handle situations such as this. d) shays' rebellion encouraged others to rebel and eventually led to the overthrow of the first established government in the united states.