Question

to answer these questions, use the diagram below.
diagram of two potted flowers, one with 10 ml fertilizer added and both with 200 ml water
according to the diagram, which question is being tested?
∘ do flowering plants grow taller when watered with salt water?
∘ how much fertilizer do flowering plants need?
∘ does adding fertilizer cause flowering plants to grow taller?
∘ what is the best kind of fertilizer that a gardener can give a flowering plant?

Explanation:

The diagram shows two plants: one gets 10 mL fertilizer + 200 mL water, the other only 200 mL water. The variable tested is fertilizer addition, and the likely outcome measured is growth (e.g., height). This matches the question about whether fertilizer causes taller growth. Other options are irrelevant (salt water not shown, amount/kind of fertilizer not varied).

Answer:

Does adding fertilizer cause flowering plants to grow taller?