A. Every day, glands in the lining of your nose, throat, airways, stomach, and intestinal tract produce about 1 to 2 quarts of mucus -- a thick, wet substance that moistens these areas and helps trap and destroy foreign invaders like bacteria and viruses before they can get into your body and cause infection.
Classical music is art music produced or rooted in the traditions of Western music, including both liturgical (religious) and secular music.
Rock and roll is one genre of music. The definition of a genre is a category of art, music or literature. An example of genre is rock and roll.