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.
The pleural space is. the area between the lungs and the chest wall. It is normally at subatmospheric. pressure, which keeps the lungs inflated. The normal pleural space has only a. few milliliters of liquid, which helps lubricate the normal to and fro motion of the. lungs during breathing.