75% species go extinct to be considered a mass extinction
The person would not have dimples.
Answer:
A. They were part of the control group
Explanation:
In a scientific experiment, the CONTROL GROUP as opposed to the experimental group is the group that does not receive the experimental treatment. This acts as a standard for comparison.
In this question, the EXPERIMENTAL VACCINE is the experimental treatment or independent variable that was added. The five animal test subjects that was injected with this vaccine are called the EXPERIMENTAL GROUP while the other five test subjects that were rather injected with a PLACEBO are called CONTROL GROUPS.
Option A I guesss. Not sure
