Question

A group of scientists were studying the growth of bacteria. It is their hope that they will be able to induce the bacteria to grow and metabolize oil as a food source. They have taken three samples of Escherichia coli and are growing them on nutrient agar plates. The scientists used three conditions to test the E. coli bacteria. The first group was grown at 37°C on plain nutrient agar plates. The second group was grown at 37°C on plain nutrient agar plates with a 5% oll solution. The third group was grown at 37°C on plain nutrient agar plates with a 20% oil solution. The results of the experiment are listed in the graph below. What is the independent variable?

A.
The type of bacteria used.
B.
The nutrient agar.
C.
The nutrient agar with oil
D.
The number of days the bacteria grew.

Answer 1

the type of bacteria used

Step-by-step explanation: