Veins would be the correct answer if I am not mistaken
The importance of this compartmental arrangement is the fact that the mediastinum region of the body houses essential organs. The region contains the thymus, pericardial cavity, trachea, esophagus and major blood vessels. The separation provides these body parts with a barrier of tissues. The mediastinum also separates one lung from the other. This is functionally important as it allows one lung to work independently of the other in cases where one may be diseased or injured.
Topsoil (horizon A):Very rich in humus(dead organic matter like plants) and minerals.
Subsoil (horizon B):less rich in humus and minerals
Weathered Rock (horizon C):Little or no plant life due to it being all rock
Hope this helps :)
