S Your new gas furnace may have been installed in one of two. ways, as a direct-vent (2-pipe-Fig. 2) application or as a. non-direct vent (1-pipe-Fig. 3) application. S In a direct-vent (2-pipe) application,your furnace uses air. from outside the home for combustion and ventsflue gas to the. outdoors.
For the biological concept, see Anti-predator adaptation. A defence mechanism is an unconscious psychological mechanism that reduces anxiety arising from unacceptable or potentially harmful stimuli. Sigmund Freud was one of the first proponents of this construct.
Combination Defenses. A third type of defense that can be deployed is the combination or Nickel defense. With combination defenses, some of the players are assigned to play person-to-person while the rest of the defenders play zone. Combination defenses are usually deployed in an effort to stop or neutralize great individual offensive players.