What structure of the respiratory system allows for gas exchange

alveoli
pharynx
nose
trachea

Because of its structure the cell membrane is known as a phospholipid ? a.bilayer b.molecule c.fluid d.barrier

Looking at this image, what relationship can be drawn from it? the lower the degree of latitude, the lower the degree of temperature there is no relationship between latitude and temperature the higher the degree of latitude, the higher the degree of temperature the lower the degree of latitude, the higher the degree of temperature

How can a geological time scale best be reconstructed? a) comparing vestigial structures in living species b) comparing homologous structures in living species c) examining homologous structures in fossil remains d) examining the written records of scientists from past cultures