1. A potometer is made using a glass U-tube, filled with water and mounted on a
stand. In one end of the U-tube, a shoot of a plant is placed and in the other end, a
pipette is placed which can be used to measure the decrease in water level. The
diagram below shows the potometer being used in an experiment.
Both the potometers are placed in well-lit rooms.
All the other conditions except for the conditions mentioned are the same for both
potometers.

For which of these purposes is a potometer likely to be used?
1. To measure the rate of transpiration
2. To measure the rate of photosynthesis
3. To estimate how long a plan can survive without roots
4. the growth of plants under different conditions.