Short answers, pulled from the story.
Violoncello is an Italian word meaning "little violone." Violone itself meant "big viola," so the name contains both the augmentative suffix "-one" (big) and the diminutive "-cello" (little). By the turn of the 20th century, musicians shortened it to "cello."
The cello is tuned in perfect fifths, starting from C2 (two octaves below middle C), then G2, D3, and A3. These intervals are the same as the viola but an octave lower.
The earliest surviving cellos were made by Andrea Amati, the first known member of the celebrated Amati family of luthiers. The cello known as "the King," built between 1538 and 1560, is one of the oldest known examples and is held by the National Music Museum in South Dakota.
A wolf tone is an unpleasant growling sound that occurs when a played note of E or F approaches the natural resonating frequency of the cello body, causing near-resonance and a beating interference. It can be addressed by modifying the cello front plate, repositioning the soundpost, or attaching a wolf tone eliminator placed on the strings between the tailpiece and the bridge.
Rostropovich inspired, commissioned, and premiered dozens of new works in the 20th century. Among the pieces written for him, Prokofiev's Symphony-Concerto, Britten's Cello Symphony, the concertos of Shostakovich and Lutoslawski, and Dutilleux's Tout un monde lointain have all entered the standard repertoire.
The cello appeared in Beatles songs including "Yesterday," "Eleanor Rigby," and "Strawberry Fields Forever" in the 1960s, and in Pink Floyd's 1970 instrumental "Atom Heart Mother." Groups like Apocalyptica built their sound entirely around cellos playing Metallica songs, and the instrument featured in Rihanna and Ne-Yo's 2007 American Music Awards performance.