The CO2
The CO2 is a big/serious problem, the biggest problem in the world. The CO2 is a element of the periodic table. Usually is a gas but sometimes can form diamonds!!!!.
              PROBLEMS                                              ADVANTAGES     
    It's toxic                                                              It's good for the photosynthesis
    It's dangerous for the forest                               It's good for the petrol
    Create the Global warming
    Create the  greenhouse effect
The conclusion is that the CO2 it's bad, but also have good things for the plants and technology