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.
Pulmonary trunk: A vessel that arises from the right ventricle of the heart, extends upward, and divides into the right and left pulmonary arteries that convey unaerated blood to the lungs.hen the right ventricle contacts, the blood inside it is put under pressure and the tricuspid valve between the right atrium and ventricle closes. The only exit for blood from the right ventricle is then through the pulmonary trunk.