data(CO2)
CO2.plot <- ggplot(data = CO2, aes(x=conc, y=uptake, colour= Treatment)) +
              geom_point() +
              xlab("CO2 Concentration (mL/L)") +
              ylab("CO2 Uptake (umol/m^2 sec)") +    
              ggtitle("CO2 uptake in grass plants")
print(CO2.plot)