Why should someone vote for a left wing party?

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.

The symbols found on the map below indicate where fossils have been found in the same layer of sediment. each unique symbol represents fossil locations of a particular species.

Which of the following items would serve as a primary source for a historian studiying the american civil war