Four.
Most symphonies have four movements, although composers are free to give their symphonies as many or as few movements as they like. The classical symphony as perfected by Haydn and Mozart almost without exception consisted of four movements. Beethoven connected the third and fourth movements of his 5th Symphony. Since that time it has varied more. For instance, Samuel Barber's first symphony is in one continuous movement with four differing sections. Cesar Franck's is probably the most famous three-movement symphony.
4 usually.
Both of these composed followed the fast-slow-fast formation for symphonies. Haydn and Mozart worked to develop the sonata form in symphonic works. They introduced a Minuet and Trio as third movement before the last movement.
Usually 4, but there can sometimes be 2 or 3.
Mozart had many famous symphonies, but the last three - often referred to as the 'final trilogy' - are regarded by many as his greatest symphonies. These were written in 1788, in the summer before his death. See the Web Link to the left and look for links to Symphonies 39, 40, and 41.
There are many different harmonies displayed in Wolfgang Amadeus Mozart's Symphony No. 40, even in the first movement. Wikipedia will tell you all the specifics on them, but there are lots, not just one.
Mozart has had many amazing symphonies. such as his last and most famous one #41 aka Jupiter.
3: Allegro, Andante, and Presto
3 complete concertos, and two movements of another.
4 Movements: 1: Poco sostenuto-vivace 2: Allegretto 3: Presto 4: Allegro con brio
4
Dmitriy Shostakovich's Symphony no. 5 in d minor has four movements, designated by their tempos: Moderato, Allegretto, Largo, and Allegro non troppo. Source: http://www.cl.cam.ac.uk/~mn200/music/shostakovich/fifth-symphony.html