ACT Experimental Results practice question

Experiment 1: 10 bean plants were grown in identical pots with 100 mL of water daily. Control group received no fertilizer. Treatment group received 5g of Fertilizer X weekly. Average height was recorded after 4 weeks. Results: Control group avg height = 15 cm; Treatment group avg height = 22 cm.

A student hypothesized that increasing the concentration of fertilizer would lead to increased plant growth. Which experiment, if conducted, would best test this hypothesis given the previous data?

More Experimental Results questions