Red blood cells, also known as RBCs, red cells, red blood corpuscles, haematids, erythroid cells or erythrocytes, are the most common type of blood cell and the vertebrate's principal means of delivering oxygen to the body tissues—via blood flow through the circulatory system. RBCs take up oxygen in the lungs, or gills of fish, and release it into tissues while squeezing through the body's capillaries.
this is about red blood cells but what are you asking
 
        
                    
             
        
        
        
<span>Hydrosphere means water-sphere.
The only answer that talks about water is "Water moves between Earth’s surface and the atmosphere" </span>
        
                    
             
        
        
        
Answer:
Evolution
Explanation:
Evolution is a gradual change in a population that occurs overtime in a species.
 
        
             
        
        
        
A theory that states that only the organism with traits that are useful to the environment survive. For example, short-neck giraffes would’ve died out years ago as they can’t reach the trees nor eat grass on the ground.