Answer:
Arteries carry oxygenated blood away from the heart. Veins carry the blood back to the heart. Veins contain valves that ensure blood flows in only one direction. Arteries don’t require valves because pressure from the heart is so strong that blood is only able to flow in one direction.
Explanation: 
 
        
                    
             
        
        
        
A whole skeletal muscle is considered an organ of the muscular system. From a sample response:)
        
                    
             
        
        
        
Answer:
D. seafloor spreading
Explanation:
If you explore two oceanic plates at a convergent boundary , you will observe seafloor spreading.
 
        
                    
             
        
        
        
Fat; they store twice as much energy per gram
        
             
        
        
        
Answer:
The fibularis longus  
Explanation:
The fibularis longus starts at the top of the fibula and attaches to the first metatarsal bone of the foot.
It has two functions:
- Eversion of the ankle (turning the foot outwards)
 - Plantarflexion (the movement like standing on tiptoe or depressing a gas pedal)