Question

A scientist claims that he has protected animal test subjects from a newly mutated virus using an experimental vaccine.The experimental vaccine was injected into five animal test subjects. The scientist also injected a placebo vaccine into five other animal test subjects.One month later, all of the test subjects were exposed to the mutated virus. The subjects that received the vaccination showed no sign of the disease and blood tests confirmed the presence of antibodies against the disease, but the subjects given the placebo developed symptoms of this condition.Why did one group have a placebo injected before being exposed to the virus?A) They were part of the experimental groupB) They would be protected from the diseaseC) They would be exposed to a weaker form of the virusD) They were part of the control group

Answer 1

Answer:

The correct answer is option D. they were part of the control group.

Explanation:

A control group is a group of subjects different from the other test subject as they did not get the independent variable's effect on them and separated from the rest of the experiment. This group of subjects is used to rule out any other explanation of the effect of the independent variable.

In this experiment, subjects that received a placebo injection are the control group as they did not expose to the mutated virus and there are the presence of antibodies in the blood.