What is the study of how muscle groups work and what keeps them going?
endocrine

circulatory

skeletal

nervous

Explanation:

Cirultary:This system works hand-in-hand with the respiratory system to facilitate the exchange of oxygen and carbon dioxide within the blood per the alveoli in the lung

Skeletal:The skeletal system is comprised of 206 bones in total and consists of several different types of bones such as long, short, flat, irregular and sesamoid. It also consists of all the joints, cartilage, tendons and ligaments within the body. The primary functions of the skeletal system are locomotion, support of the body, and the protection of internal organs such as the brain, heart, and lungs.

Nervous:The nervous system is made up of two major parts: the central nervous system (CNS) and the peripheral nervous system (PNS). The central nervous system is made up of the brain and spinal cord and acts as the main control system for the body. The peripheral nervous system is made up of all the nerves and ganglia (nerve cell clusters) found outside of the central nervous system; its role is receiving information from various stimuli and sending it to the brain.

i believe it is the last one. im sorry if im wrong!

answer; teamwork;