2. Наиболее распространенный источник инфекции, источник болезни, древние люди, защитный наружный слой, подобный эффект, предотвращать, проксимальная поверхность, слизистая оболочка.
3. 1) Bacteria. These one-cell organisms are responsible for illnesses such as strep throat, urinary tract infections and tuberculosis. Viruses.
2) The digestive functions of saliva include moistening food, and helping to create a food bolus, so it can be swallowed easily. Saliva contains the enzyme amylase that breaks some starches down into maltose and dextrin. Thus, digestion of food occurs within the mouth, even before food reaches the stomach.
3) the last line of defense is that position where the mission is to hold enemy forces and not allow them to pass.
4. through cuts on the skin, food, gastric juice, more favorable conditions, harmless, destruction