1. Подставьте, где необходимо, предлоги. to of (4) by with
The oral cavity is a fearsome orifice demanding constant gratification and full 1) ............. microorganisms, some 2) ............. which are potentially harmful. The oral mucosa is highly resistant 3) ............... its indigenous flora and has many defences including the comprehensive suppression 4) .............. potential pathogens 5) .............. microorganisms 6) .............. low virulence. Saliva also has its antibacterial effect. But any lowering 7) ............... these defences potentiates oral infection.