A pathologist is carrying out an autopsy. Upon opening the chest cavity, the pathologist sees a thick, fibrous tissue surrounding the heart. This is likely:

Answer: Connective tissue.

Explanation:

The cardiac muscle consists of four bands which is connective tissue as the collagen which encircles the heart valves, aorta and pulmonary trunk.

The cardiac skeleton is fibrous skeleton system of the heart. This fibrous nature of the connective tissue provides it strength and anchors the valves.

The connective tissue in the heart allows the heart to pump blood all the time means the energy and strength is fulfilled by these tissues.