Robert Koch verified the germ theory of disease in 1890 in experiments using rabbits. He first isolated a pathogen (Bacillus anthracis) from a sick rabbit and noted that the organism was not present in healthy rabbits. Bacillus anthracis is the causative agent of anthrax, which leads to illness and death in the rabbits. He next injected healthy rabbits with the strain. Other rabbits may have been mock injected with a sterile solution. For this experiment, identify the independent variable, the dependent variable, the control group, and the treatment group.

Question

Robert Koch verified the germ theory of disease in 1890 in experiments using rabbits. He first isolated a pathogen (Bacillus anthracis) from a sick rabbit and noted that the organism was not present in healthy rabbits. Bacillus anthracis is the causative agent of anthrax, which leads to illness and death in the rabbits. He next injected healthy rabbits with the strain. Other rabbits may have been mock injected with a sterile solution. For this experiment, identify the independent variable, the dependent variable, the control group, and the treatment group.

dependent variable
treatment group
independent variable
control group
injection with Bacillus anthracis
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illness from Bacillus anthracis
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rabbits that were mock injected
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rabbits that were injected with Bacillus anthracis

Answer 1

The independent variable is the injection of Bacillus anthracis. The dependent variable is the illness caused by Bacillus anthracis. The treatment group is the rabbits that were injected with Bacillus anthracis. The control group is the rabbits that were mock injected with a sterile solution.