D hope that helps good day
True Minerals are naturally occurring and not manufactured. However, please show the answer choices so I could answer it.
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.
