The stem of the plant should be cut at least three to four inches above the surface level. The glass capillary should be tightly fixed with the stem. The initial water level and the final water level should be carefully noted. The droplets on the leaves should be observed and conclude that these drops are not from transpiration.
Although greenhouse gases such as water vapor, CO2, and methane naturally occur in smaller amounts, they absorb and release heat energy more efficiently than gases like N and O. (Nitrogen and Oxygen.) So I would say (1) is the answer
