Which system and rationale best pairs with the musculoskeletal system to ensure fluid movement of the human body? 1. the digestive system, to obtain the energy that is needed to move the muscles with smooth, coordinated effort 2.the nervous system, to send and receive messages from the brain to move the muscles with smooth, coordinated effort 3.the muscular system, to flex, extend, and rotate the muscles with smooth, coordinated effort 4.the respiratory system, to provide oxygen to the muscles so they will move with smooth, coordinated effort

The correct answer is option 3, that is, the muscular system, to extend, flex, and rotate the muscles with smooth, and coordinated effort.  

The musculoskeletal system provides support, form, movement, and stability to the body. It comprises the bone of the skeleton, cartilage, muscles, ligaments, tendons, joints, and other connective tissue, which holds and supports organs and tissues together.  

The flexing, extension, and rotation of the muscles with smooth and coordinated effort makes sure the movement of fluid in the human body.  

Answer-

C: The muscular system, to flex, extend, and rotate the muscles with smooth, coordinated effort.