Submit. Â· just now. Report Abuse. when a rock is subjected to severe heat, then dramatic cooling onion weathering takes place. This is a form of physical weathering. The sudden change of temperature weakens the outer layer of rock and it will crumble away, this happens to rocks in the desert.
Definition. Common arterial trunk (CAT) is characterized by a single arterial trunk that arises from the base of the heart and gives origin to the systemic, coronary and pulmonary circulation. A large ventricular septal defect (VSD) is almost always present.
As you read about circular pathways, notice that there is an occasional, very large artery referred to as a trunk, a term indicating that the vessel gives rise to several smaller arteries. For example, the celiac trunk gives rise to the left gastric, common hepatic, and splenic arteries.