What might be a key factor affecting plant growth in an experiment?

The amount of sunlight the plants receive is a crucial factor affecting plant growth because sunlight is essential for photosynthesis, the process by which plants convert light energy into chemical energy in the form of glucose. Sufficient sunlight ensures that plants can produce the energy they need to grow, develop, and reproduce. Without adequate light, plants may exhibit stunted growth, yellowing leaves, or even death.

While other factors, such as soil pH and fertilizer type, also play significant roles in plant health, they are often secondary to the immediate need for light. For example, if a plant does not receive enough sunlight, no amount of nutrient-rich soil or appropriate fertilizer will compensate for the lack of energy necessary for growth. Hence, sunlight is fundamental and cannot be overlooked when considering experimental conditions for plant growth.