Can someone explain this part for me

The concluding paragraph of the cover letter should include all of the following except: for apex - college and career semester 2 answer - b. contact information

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.

U. s. history i which statement is true? the missouri compromise ended slavery in the south. the compromise of 1850 eliminated slavery only in the south. the missouri compromise postponed the issue of slavery. the compromise of 1850 ended slavery in every region of the united states.