question: What is regulated by feedback mechanisms?
choices.text: estrogen kinase Otoacoustic pigmentation ducks prokaryotes birds fish
choices.label: A B C D E F G H
fact2: Female hormone is estrogen.
combinedfact: estrogen is regulated by feedback mechanisms.
formatted_question: What is regulated by feedback mechanisms? (A) estrogen (B) kinase (C) Otoacoustic (D) pigmentation (E) ducks (F) prokaryotes (G) birds (H) fish