Answer:
1. The two gases making the highest relative contribution to the greenhouse gases are: "CO2 and CH4."
2. The effect of increasing amount of greenhouse gasses is: "All of the above"
3. Which one of the following is a wrong statement?: "Eutrophication is a natural phenomenon in freshwater bodies"
4. The major contributors to the greenhouse gases are: "All of the above"
Explanation:
CO2 is carbon dioxide, and CH4 is methane. Also, the greenhouse gas effect is natural, except, the amount of greenhouse gases is not.