Question

you want to experiment if miracle - grow will increase your tomato crop. what is your dependent variable?
water
whether or not plants get miracle - grow
sunlight
weight or number of tomatoes

Explanation:

In an experiment, the dependent variable is what is being measured and is affected by the independent variable. Here, the goal is to see if Miracle - grow increases the tomato crop. So, the amount (weight or number) of tomatoes is what is being measured and is dependent on whether Miracle - grow is used or not.

Answer:

weight or number of tomatoes