Exercise 7: Experimental Variables Determine the variablestested in the each of the following experiments. If applicable,determine and identify any positive or negative controls.Observations 1. A study is being done to test the effects ofhabitat space on the size of fish populations. Different sizedaquariums are set up with six goldfish in each one. Over a periodof six months, the fish are fed the same type and amount of food.The aquariums are equally maintained and cleaned throughout theexperiment. The temperature of the water is kept constant. At theend of the experiment the number of surviving fish is surveyed. A.Independent Variable: B. Dependent Variable: C. ControlledVariables/Constants: D. Experimental Controls/Control Groups: 2. Todetermine if the type of agar affects bacterial growth, a scientistcultures E. coli on four different types of agar. Five petri dishesare set up to collect results: ? One with nutrient agar and E. coli? One with mannitol-salt agar and E. coli ? One with MacConkey agarand E. coli ? One with LB agar and E. coli ? One with nutrient agarbut NO E. coli All of the petri dishes received the same volume ofagar, and were the same shape and size. During the experiment, thetemperature at which the petri dishes were stored, and at the airquality remained the same. After one week the amount of bacterialgrowth was measured. A. Independent Variable: B. DependentVariable: C. Controlled Variables/Constants: D. ExperimentalControls/Control Groups: