what is the difference between tuba and sousaphone
Sousaphone The sousaphone is a valved brass instrument with the same tube length and musical range as other tubas. The sousaphone's shape is such that the bell is above the tubist's head and projecting forward. The valves are situated directly in front of the musician slightly above the waist and all of the weight rests on the left shoulder. The bell is normally detachable from the instrument body to facilitate transportation and storage. Except for the instrument's general shape and appearance, the sousaphone is technically similar to a tuba.
Vein Veins are less muscular than arteries and are often closer to the skin. There are valves in most veins to prevent backflow.
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Alonso Álvarez de Pineda