C. From carbon dioxide in the atmosphere
        
                    
             
        
        
        
This can happen because you have recessive and dominant characteristics passed down. So you can get a totally different chromosome that doesn't come from your parents because your grandparents may have had it or great grand parents, the line keeps going .
        
             
        
        
        
It absorbs oxygen while at the same time releases carbon dioxide across its surface  
        
             
        
        
        
Ligaments connect one bone to another bone. Therefore, they allow a joint to form, because joints are where two or more bones connect. 
Take your knee joint for instance (***see attached pic***). The knee joint is formed by the connection of the femur (your thigh bone), the tibia (your shin bone), and the fibula (the other long bone in your lower leg). In order for all of these bones to connect there are many ligaments in the knee joint that keep the bones connected and in place.  A well known example of one of these ligaments in the knee joint is the ACL (anterior crucate ligament), which is commonly torn in sports, namely football. Most people have heard of this ligament because it receives a lot of media attention since tearing it can greatly alter or even end professional athletes' careers.