In the Model 2, the one condition that has been varied among the four trials is the amount of sunlight reaching the plant during photosynthesis.
What is a variable?
A variable is a factor which can alter or affect the result of an experiment when it is changed or altered.
In the given experiment to determine the rate of evolution of oxygen gas in the aquatic plant, the variables involved include the amount of sunlight.
Since oxygen gas is evolved during photosynthesis which requires sunlight, changing the amount of sunlight will affect the rate of photosynthesis.
In the Model 2, the amount of sunlight reaching the plant is varied.
In conclusion, the rate of photosynthesis increases or decreases with increase or decrease in the amount of sunlight.
Learn more about photosynthesis at: https://brainly.com/question/3529377
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