It's called t<span>he trachea.</span>
Answer:
b progesterone
Explanation:
The plug is formed as soon as there is implantation of fertilized eggs. The thickness of the cervical mucus becomes different as hormone levels changes in pregnancy.
The progesterone, encourages the production of thick fluid/ mucus which brings about the formation of a plug. This prevents bacteria from getting into the uterine cavity.
