Given a scientific question, generate a correct answer to it.
--------
Question: What is the term for a loop in which a product feeds back to control its own production?

Answer: feedback mechanism

Question: What kind of interference is observed when the paths differ by a whole wavelength, and the waves arrive in phase?

Answer: constructive interference

Question: What is the term for polyatomic ligands with two or more donor atoms?

Answer:
chelates