Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) What I need to know about Gas ?
    ### Response:
    Gas is air in the digestive tract. Gas leaves the body when people burp through the mouth or pass gas through the anus*the opening at the end of the digestive tract where stool leaves the body.
                
Everyone has gas. Burping and passing gas are normal.
    