In an experiment examining how sunlight affects plant height, which variable is independent?

• A. Plant height
• B. Sunlight amount
• C. Soil type
• D. Water amount

Answer: (B)

When you design an experiment, the variable you purposely change to see its effect on another outcome is the independent variable. In this setup, you change how much sunlight the plant receives and then observe how tall it grows. That makes sunlight amount the independent variable. The plant height is the result you measure, so it’s the dependent variable. Soil type and water amount would typically be kept constant to ensure any observed effect on height is due to changes in sunlight, not other factors.