Answer:

Theobald Boehm brought several changes to the flute. The changes include:

- Kind of metal used: Boehm introduced the use of silver for the flute, which replaced the previous material, which was typically made of wood or ivory.

- Keyhole positions: Boehm rearranged the position of the keyholes to allow for easier finger placement and improved intonation.

- Size of the finger holes: Boehm made the finger holes larger, which allowed for a more resonant and powerful sound.

- Length of the pipe: Boehm redesigned the shape and length of the flute's bore and added a conical section, which improved the intonation and timbre of the instrument.

So, the correct answers to your question would be:

- Kind of metal used

- Keyhole positions

- Size of the finger holes

- Length of the pipe