Answer:
The concentration gradient of oxygen in your lungs wants to flow toward homeostasis and oxygen is bound on red blood cells by hemoglobin, along with the attraction of oxygen to hemoglobin. The concentration gradient from carbon dioxide from the capillary to the lungs. There is more oxygen in your lungs (alveoli) than there is carbon dioxide and everything want to reach homeostasis, or level amounts on both sides. 
Explanation:
 
        
             
        
        
        
Well, an endoskeleton is an internal skeleton, like humans have.
Pro: Bones do not get broke as easily, since they are inside of the body. Bones that break also heal more quickly in an endoskeleton, since they have tissue and blood surrounding it and transferring nutrients.
Con: The flesh can get easily damaged. There is no shedding with endoskeletons, so a new skeleton cannot be grown in the event of an injury. 
 
        
             
        
        
        
Answer:
heh
Explanation:
you shouldn't be questioning if you're in a live test
 
        
             
        
        
        
<span>The nitrogenous base pairs, which are linked by hydrogen bonds that also hold the strands together, are between this backbone. However, the nitrogenous bases, which are adenine, thymine, cytosine and guanine, pair up so that cytosine only pairs with guanine and adenine links up with thymine.</span>