Answer:
Bones 
Explanation:
Bones are tissues that provide the body with rigidity. It also acts as the body's supporting structure. 
The bone helps to maintain the body's shape at all times and provide a surface for the attachment of muscles. Joints are the points of contact between two bones. The bones, muscles and joints are very important in the locomotion(movement) process because there’s a synergy between them.
 
        
                    
             
        
        
        
Yes because places that are poor can’t pay for as many treatments as others
        
             
        
        
        
1983-1984 was when it was discovered