Final answer:
The three experimental groups are plants grown in red, blue, and green light, with white light serving as the control. The experiment aims to investigate how different colors of light affect plant growth.
Step-by-step explanation:
The three experimental groups in the given experiment are plants grown in red light, blue light, and green light. The fourth group, grown in white light, serves as the control group.
The reason for these experimental groups is to investigate how different colors of light affect plant growth. Each color of light has a different wavelength and energy level, which can influence the plant's photosynthesis and other physiological processes. By comparing the growth of plants in different colored light, the experiment aims to determine which color of light promotes the most growth and which color inhibits growth.
For example, if the plants grown in red light exhibit the highest growth, it suggests that red light is most conducive to plant growth. On the other hand, if the plants grown in blue or green light show better growth, it indicates that these colors of light are more favorable for plant growth.