The American black bear lived during the same period as short-faced bears (Arctodus simus and A. pristinus) and the Florida spectacled bear (Tremarctos floridanus). These Tremarctine bears evolved from bears that had emigrated from Asia to North America 7â8 ma.
A plenum space is a part of a building that can facilitate air circulation for heating and air conditioning systems, by providing pathways for either heated/conditioned or return airflows, usually at greater than atmospheric pressure.
Furnace Plenum. A plenum is a compartment, air space or chamber that is filled with air that is then distributed elsewhere. A furnace plenum then, is such an air chamber that gets filled directly (and quickly) by a large blower that is above, below or adjacent to it. Air ducts connected to a furnace or heater plenum carry this air to various registers around a house or building.