What data would be most helpful to support the claim that the population of a certain plant is dependent on the rainfall in its habitat

1. Rainfall amounts and number of these plants in a certain habitat over several years

2. The heights and number of leaves produced by these plants under different moisture conditions

3. The average amount of water absorbed by the roots and given off by the leaves of these plants

4. The amount of water retained in the soil in the area where the plants live