Astudent is doing an experiment to find the concentration of ammonia, a component of fertilizer, that affects the life cycle of the aquatic worm. the amount of fertilizer in this experiment is the a) control factor b) dependent variable c) independent variable d) optimum factor e) standard variable

Answer is C. Independent variable.

Because the amount of fertilizer can affect the life cycle of aquatic worm, making it an independent variable that influences the result.

Hope this helps. - M

C) Independent Variable

In an experiment, you have your independent variable, your dependent variable, and your control.

Your independent variable, IV, is what you're changing/manipulating throughout an experiment.
Your dependent variable, DV, is usually what you're measuring and could change in response to you changing your independent variable.
Your control factor is something that you want to keep the same throughout the experiment. Keeping these things the same will help your IV to be the only thing affecting your DV, giving you more accurate results.

For your experiment, the student if trying to find the effect of the concentration of ammonia, depending on the amount of fertilizer, (IV) on the life cycle of the worm (DV). The amount of fertilizer is your independent variable because you'll be changing that in order to measure your dependent variable, the length of the life cycle of the worm.

The rest don't make sense so i say the first one.