<span>Enzymes are called biocatalysts because they function in chemical reactions that involve living organisms [biologial organisms]. Enzymes generally increase the rate of metabolic reactions by lowering the activation energy, making it easier for the reaction to occur easily and rapidly. Without enzymes, some metabolic reactions may take a very long time before they are completed. Enzymes used in laboratory chemical reactions are not biocatalysts because they are not catalysing reactions in biological organisms. </span>
The thoracic cavity, also called the chest cavity, is a cavity of vertebrates bounded by the rib cage on the sides and top, and the diaphragm on the bottom. The chest cavity is bound by the thoracic vertebrae, which connect to the ribs that surround the cavity. The thoracic cavity is actually composed of three spaces each lined with mesothelium, a special film-like tissue that separates vital organs. The pleural cavities surround the lungs, while the pericardial cavity surrounds and protects the heart.
Answer:B
Explanation:Postganglionic sympathetic nerve pathway
