(a)[1]
State the percentage of clean dry air that is oxygen. Round your answer to the nearest whole number.
(b(i))[2]
Name the method used to separate oxygen and nitrogen from liquid air.
(b(ii))[1]
State the property of oxygen and nitrogen that makes it possible to separate these gases by this method.
(c)[2]
Complete the diagram to show the electron structure in one $\text{CO}_2$ molecule. Include only the outer electrons.
(d)[3]
The information in the graph is a cause for global concern. Explain why.
(e)[1]
Name the process in the carbon cycle by which plants take carbon dioxide out of the atmosphere.