tuba
The double bass
All instruments produce a pitch.
The piccolo is the highest pitched instrument in the woodwind family
flute
In a string orchestra, an orchestra with violin, cello, viola, and bass, the bass is the largest and lowest instrument. However, if you were looking for the largest string instrument in a full orchestra, the piano would be the instrument for which you are looking.
Gimmick quad upright bass violins or contrabass claim to have ultra low frequencies. It takes a machine, two people, or a giant to play one. Traditionally, for practical use, the pipe organ with 26'+ stops is the lowest pitch.
That would be the Double Bass, also knows as a Bass Fiddle.
All three are true, assuming the definition of "tuned" is flexible. Any percussion instrument makes a certain sound, and most, if not all, will have an element of pitch which can be changed by tuning the instrument (shaving wood off of a woodblock, tightening a drum head, etc). The other two questions are definitely true - idiophones include the snare and timpani (kettledrum), and tuning an instrument means setting it to a certain pitch.
i play instrument all day long
All drums are in the percussion instrument family.
The tuba. This large brass member is pitched incredibly low, and is the lowest pitched brass instrument.
Oboe I find that hard to believe. Not piccolo? umm it is deff the oboe :)