You are studying the effect of fertilizer on the yield of tomatoes. In order to do this, you use the same type of tomato seedlings, make sure they get the same amount of water, and are exposed to the same amount of sunlight. What type of experimental variable is the yield of tomatoes? a) dependent variable b) independent variable c) controlled variable d) none of the above

(a) is the correct option

Explanation:

Yield of tomatoes is a dependent variable

The dependent variable is something that is observable and measurable, here in this case yield of tomatoes can be calculated and measured depending on the type or concentration of fertilizer usedThe independent variable, also known as the experimental treatment is the difference or change in the experimental conditions that is chosen, here in this case it is the concentration or type of fertilizerTo ensure that only the independent variable is affecting the dependent variable, all the other factors acting upon the test situation must be kept constant, these factors that must be kept the same are called the controlled variables, or constant variablesHere in this case amount of water, exposure to sunlight and type of seedlings is kept same

The answer would be the sound waves.