Question

Conlan wants to answer the question, “Does phosphorus affect tomato fruit production?” Which statement represents a hypothesis that he can test to answer his question?
If phosphorus affects tomato fruit production, then tomatoes that are fertilized with phosphorus will have larger leaves.
If phosphorus affects tomato fruit production, then phosphorus should be added to the soil during planting.
If phosphorus affects tomato fruit production, then adding phosphorus to the soil will make tomatoes taste better.
If phosphorus affects tomato fruit production, then plants that are fertilized with phosphorus will produce more tomatoes.

Answer 1

"If phosphorus affects tomato fruit production, then plants that are fertilized with phosphorus will produce more tomatoes."

This directly links phosphorus to fruit production and is a testable prediction.