None. Saxophones don't have valves.
7 octaves
any where from 1 to maybe 3
Woodwinds
Welcome to the bass and baritone sax review section.
about four feet
Yamaha
The alto sax is generally not known as "an E flat sax", as a baritone saxophone is also in E flat.
French horn, trumpet, tuba, bar-sax (also part woodwind), baritone, euphonium (like baritone, but with straight top).
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When Adolphe Sax was experimenting with Bass Clarinets, he accidentally invented the Baritone Saxophone in 1840.
The Baritone derives from a amalgamation of many instrument inventions by the Belgium inventor Adolph Sax who also invented (unsurprisingly) the sax as well as the euphonium and many other now extinct instruments.
It's pretty easy... but everyone is different. It depends on if you know what you are doing and if its a baritone sax or just a regular baritone. This question is more of an opinion.