There are four kinds of tissues in the human body. They are muscle, nervous, connective, and epithelial tissues. Which of the following is true about all of these tissues?

 Epithelium tissue refers to the sheets of cells that cover exterior surfaces of the body, lines internal cavities and passageways, and forms certain glands. Connective tissue binds the cells and organs of the body together and functions in the protection, support, and integration of all parts of the body. Muscle tissue is excitable, responding to stimulation and contracting to provide movement, and occurs as three major types: skeletal (voluntary) muscle, smooth muscle, and cardiac muscle in the heart. Nervous tissue is also excitable, allowing the propagation of electrochemical signals in the form of nerve impulses that communicate between different regions of the body

Explanation:

answer; ///(b) it is composed of four protein chains and four heme groups;