Answer:
The independent variable is the amount of sunlight.
Explanation:
Consider the provided information.
Joshua investigates the effect of varying amounts of sunlight on the rate of plant growth.
He experiments by exposing seedlings to different amounts of sunlight each day.
He stops the experiment when each seedling reaches 20 cm in height.
The independent variable is a variable describing a quantity controlled in an experiment. A dependent variable is a quantity whose value depends on such manipulations.
The amount of sunlight is the factor directly controlled by Joshua.
The other factors, such as rate of plant growth and time needed to reach 20 cm, depend on the amount of sunlight. They are dependent variables.
The amount of sunlight is the factor directly controlled by Joshua.
The other factors, such as rate of plant growth and time needed to reach 20 cm, depend on the amount of sunlight. They are dependent variables.
Hence, the independent variable is the amount of sunlight.