What is the independent variable in an experiment testing how sunlight exposure affects plant growth?

• A. The type of plant being grown
• B. The amount of sunlight exposure (hours per day)
• C. The amount of water given
• D. The temperature of the room

Answer: (B)

Independent variable is the factor you deliberately change to see its effect. In this experiment, you adjust the amount of sunlight exposure each plant receives per day to observe how it affects growth. That makes sunlight hours the independent variable. The plant’s growth is what you measure, the dependent variable. Other factors—type of plant, amount of water, and room temperature—are kept the same so any differences in growth can be attributed to the sunlight changes.