The first one because just think about how light oxygen or air is
D I believe, in the picture that is attached explains
A form of asexual reproduction of a plant. Only 1 plant is involved and the offspring is the result of the 1 parent. It is genetically identical to the parent.
Answer:
1)the process being studied in the picture is transpiration I guess
3)the pot is covered with plastic sheet to trap the water (vapour) which is being evaporated