Capillaries are one cell thick and so this makes them very thin. capillaries are also arranged in networks known as capillary beds, and thus multiple capillaries are spread over a large area.
        
             
        
        
        
The answer is B between respiration and combustion
        
             
        
        
        
The right answer is DNA. That consist of a sugar, deoxyribose, a phosphate and a nitrogen-containing base