several digital scales. a wet paper towel. several identical plant seeds. different sizes of containers.
I am hesitating between 4 options to answer the following question, which option should I choose?
Question: A student hypothesizes that the amount of water a plant receives will affect how long it grows before reaching maturity. To test this hypothesis, the student will need
Possibilities:
- several digital scales.
- a wet paper towel.
- several identical plant seeds.
- different sizes of containers.

several identical plant seeds.