Answer:
Stabilizing selection
Explanation:
Stabilizing selection is the most common form of natural selection that is not easy to notice in a population as the change is less drastic. It occurs when average or intermediate phenotypes of a trait in a population are favored, while the extreme phenotypes of that trait are not favored by the forces of natural selection. Over time, intermediate or non-extreme traits become more common in the population, while extreme traits become less common.
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.

In humans, the medulla region of the brain is mainly responsible for the regulation process of respiration. It is also called the respiratory rhythm centre. The chemosensitive area located near the respiratory centre sends signals across nerve impulses to alter the rate of expiration to eliminate compounds.
The light needed for photosynthetic reactions tends to be more reds and purple wave lengths. The Green wavelength is reflected. Filtering out the green light will stunt the light reactions of the plant.
Answer:
B. Protein is composed of DNA which is produced in the cell
Explanation: