Answer: High Frequency waves by method of compression bone conduction
Explanation: in this, vibration of the bones of the skull and sometimes, arguably soft tissues leads to the production of sounds. The outer and middle ear is bypassed in this method of sound production. Sound reaches the inner ear directly and its a process largely involved in designing hearing aids.
Pineapples, unlike most other fruit, contain an enzyme called bromelain, that breaks up the gelatin into it's amino acid building blocks. [Enzymes are biomolecules that catalyze chemical reactions; most of them are proteins themselves.] Due to the bromelain, your jello doesn't become (or stay) solid.
E) it produces food that do not contain artificial compounds