Question

list the possible independent variable in this experiment.

Explanation:

The experiment involves plant growth with different water drop sizes (or amounts) shown before. The independent variable (IV) is what's manipulated, so water quantity (or size of water drops) is the IV as it's changed to observe plant growth (DV).

Answer:

IV: Amount (or size) of water given to plants
DV: Growth of the plants (e.g., size, number of leaves)