A condensation reaction is a chemical reaction in which two molecules or moieties (functional groups) combine to form one single molecule, together with the loss of a small molecule – here OH-

Naturally occurring mandelonitrile is found in the millipede Apheloria corrugata as a defense mechanism. when Apheloria is about to be attacked, mandelonitrile decomposes enzymatically  into benzaldehyde and a poison (hydrogen cyanide).

+1 for each bond to O