Answer: Option B.
Explanation:
The first experiment of the passage shows that treatment with TGFBR1 and TGFBR2 antagonists led to lower levels of epithelial cell production. For this conclusion to be strongly valid, we want to show a positive correlation between TGFBR activity and epithelial proliferation.
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.
I looked it up and it should be D. Nerve cells :)
