What would happen if all the green plants disappear from the earth?

How do guard cells regulate opening and closing of stomatal pores?

Two similar green plants are kept separately in oxygen free containers, one in dark and the other in continuous light. Which one will live longer? Give reasons.

If a plant is releasing carbon dioxide and taking in oxygen during the day, does it mean that there is no photosynthesis occurring? Justify your answer.

Leaves of a healthy potted plant were coated with vaseline. Will this plant remain healthy for long? Give reason for your answer.