Question

A scientist sets up an experiment to test which substance (caffeine, nicotine, alcohol, or water) affects plant growth the most. What are the control variables (the things that are kept the same) in this experiment?

a) Plants, containers/pots, soil, sunlight.
b) Caffeine, nicotine, alcohol, water.
c) Temperature, humidity, time of day, music in the background.
d) Experimental group, control group, hypothesis, results.

Answer 1

The control variables in the plant growth experiment are the plants, containers/pots, soil, and sunlight.

Step-by-step explanation:

In the plant growth experiment, the control variables are the factors that need to be kept the same to ensure that they do not affect the results. These include:

• Plants: Using the same type of plants for all groups ensures that any differences in growth are not due to plant genetics.
• Containers/pots: Using the same size and type of containers ensures that plant growth is not influenced by differences in container conditions.
• Soil: Using the same type and amount of soil across all groups helps control for any variations in nutrient availability.
• Sunlight: Providing the same amount and intensity of sunlight to all plants ensures that differences in growth are not due to variations in light exposure.