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.
C. S waves travel through solids or very dense, glassy liquids. P waves travel through solids, liquids, and gasses.
Plants maintain homeostasis by keeping their stomata open just enough to allow photosynthesis to take place but not so much that they lose an excessive amount of water.
When plant cells use the food they make, the cells respire, taking in oxygen and giving off carbon dioxide.
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