Question

this illustration depicts an experiment to determine how different colored lights affects tomato plants. for this to be a \fair\ test, identify which of the following needs to be kept constant for each tomato plant. image of four tomato plants in pots with different colored lights (green, orange, blue, yellow) above them the amount of water, the color of the pot, and the method of watering. the amount of light, the color of the light, and the type of watering can. the amount of water, the amount of light, and the type of plant. the amount of water, the color of the pots, and the type of plant.

Explanation:

To conduct a fair experiment (testing how different - colored lights affect tomato plants), the independent variable is the color of the light. All other factors that could influence the growth of the tomato plants (controlled variables) should be kept constant.

• Analyzing Option 1: The color of the pot is not a factor that affects plant growth related to light, so this is incorrect.
• Analyzing Option 2: The color of the light is the independent variable (the one we are changing to test its effect), so it should not be kept constant. Thus, this option is wrong.
• Analyzing Option 3: The amount of water (affects growth), the amount of light (except for its color, the intensity/amount should be same), and the type of plant (all are tomato plants, so same type) are all factors that need to be constant to ensure that any difference in plant growth is due to the color of the light.
• Analyzing Option 4: The color of the pots does not affect plant growth related to light, so this is incorrect.

Answer:

C. The amount of water, the amount of light, and the type of plant.