Opposing pairs of muscles involved in movement are called a. tendons and ligaments. b. flexors and extensors. c. smooth and striated muscles. d. skeletal and cardiac muscles.

b. flexors and extensors

Explanation:

The flexor and extensor muscles are skeletal type muscles. They have the function of joint movement for which they work together, they bend and straighten the joints of the body.

Flexors work to bend a joint and extenders extend and straighten joints

these muscles maintain the blood pressure in the vessels. the smooth muscles are innervated by nerves of the autonomic nervous system. when the muscles contract, they cause vasoconstriction of the vessels and increase blood pressure. when the muscles relax, they enable vasodilation of the   blood vessels hence reduce blood pressure.