Question

1. A study is being done to test the effects of habitat space on the size of fish populations. Different sized aquariums are set up with six goldfish in each one. Over a period of six months, the fish are fed the same type and amount of food. The aquariums are equally maintained and cleaned throughout the experiment. The temperature of the water is kept constant. At the end of the experiment the number of surviving fish are surveyed.
   1. Independent Variable:
   2. Dependent Variable:
   3. Controls:
2. To determine if the type of agar affects bacterial growth, a scientist cultures E. coli on four different types of agar. Five petri dishes are set up to collect results:

· One with nutrient agar and E. coli

· One with mannitol-salt agar and E. coli

· One with MacConkey agar and E. coli

· One with LB agar and E. coli

· One with nutrient agar but NO E. coli

1. Independent Variable:
2. Dependent Variable:
3. Controls:

Answer 1

In the first Experiment =

A. Independent variable : size of aquarium (habitat space) B. Dependent variable : the amount of goldfish survive (size of the population) C. Controls : amount of food, type of food, aquarium cleaning, water temperature (constant supply and equally maintain)

In the second Experiment =

A. Independent variable : Type of agars, E. coli B. Dependent variable : Bacterial Growth C. Controls : temperature, petri dish size, air quality

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