1 lactase intolerance, and. 2  malabsorption of certain foods. 3  Much of the gas generated is due to microbial breakdown of foods so that gases, for example, hydrogen, carbon dioxide, and methane are generated; the odor is from other trace waste gases or compounds such as skatole and sulfur-containing substances.
Best Answer: Blood enters the heart through the right atrium, it then goes into the right ventricle to be pumped via the pulmonary artery to the lungs to be re-oxygenated. After that it heads, via the pulmonary vein, to the left atrium in the heart to be pumped around the rest of the body again via the aorta.
Infection usually enters the body wherever germs or bacteria can pass inside the body-for example through the mouth into the gastrointestinal tract, via the genitals-for exa â¦ mple during sex, or by any area that is open to the environment.