Answer:
Double Helix
Explanation:
It is called the double helix for the signature shape that a DNA strand takes.
 
        
             
        
        
        
Answer: Four pulmonary veins.
Explanation: Oxygen and nutrient rich blood will flow from the lungs back into this part called the left atrium (Or as some will call it, the left upper chamber in the heart). From there, it goes through four pulmonary veins.
Hope I could help! :)
 
        
             
        
        
        
Answer: By us people breathing in oxygen and breathing out carbon dioxide.
 
        
             
        
        
        
Answer:
The movement is caused by the convection currents that roll over in the upper zone of the mantle. This movement in the mantle causes the plates to move slowly across the surface of the Earth.
Explanation: