Serotonin is a chemical produced naturally in your brain that affects the way you feel, for example making you feel happier, calmer, or less hungry.
N-UNCOUNT
Serotonin is a chemical produced naturally in your brain that affects the way you feel, for example making you feel happier, calmer, or less hungry.
N-UNCOUNT
Collins COBUILD. Толковый словарь английского языка для изучающих язык Коллинз COBUILD (международная база данных языков Бирмингемского университета) . 2012