Respiratory effects [edit]. The PRG antagonizes the apneustic center, cyclically inhibiting inhalation. The PRG limits the burst of action potentials in the phrenic nerve, effectively decreasing the tidal volume and regulating the respiratory rate.espiratory effects [edit]. The PRG antagonizes the apneustic center, cyclically inhibiting inhalation. The PRG limits the burst of action potentials in the phrenic nerve, effectively decreasing the tidal volume and regulating the respiratory rate.
Because the ones at the bottom, the animals would have died first and soil would have covered them building a cliff and the fossils up top would have died later. 3 people found this useful.
The oldest known fossil species within Vulpes is Vulpes riffautae, which dates back to the late Miocene (which is within the Neogene) of Chad. The deposits these fossils are found within are about 7 million years old, which might make them the earliest Canidae in the Old World.he oldest known fossil species within Vulpes is Vulpes riffautae, which dates back to the late Miocene (which is within the Neogene) of Chad. The deposits these fossils are found within are about 7 million years old, which might make them the earliest Canidae in the Old World.