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.
A bobcat has many defense mechanisms that they can use against  their predators. These defense mechanisms include their sharp  claws, sharp dagger style teeth, ferocious gro â¦ wl, concealment  capabilities, and keen sense of sight.1 person found this useful. bobcat has many defense mechanisms that they can use against  their predators. These defense mechanisms include their sharp  claws, sharp dagger style teeth, ferocious gro â¦ wl, concealment  capabilities, and keen sense of sight. 1 person found this useful.