thyroida gland in the neck that produces hormones regulating growth and metabolismAn underactive thyroid can cause fatigue, weight gain, and depression.NoteAn underactive thyroid can cause fatigue, weight gain, and depression.Elon.io is an online learning platformWe have an entire course teaching IELTS Vocabulary — Band 7+ grammar and vocabulary.Start learning IELTS Vocabulary — Band 7+ now