Name the organs of external respiration

Most of the fossils found in virginia are in the coastal plain, valley, ridge, and appalachian plateau regions, best suggesting that these geographic provinces a) were once covered by seawater. b) are the oldest parts of virginia. c) have a great deal of karst topography. d) have large amounts of sedimentary rock.

When analyzing tree rings, what do scientists assume a thin ring indicates?

An example of internal feedback working to maintain homeostasis is your a. decreased respiration rate when you are studying b. decreased heart rate when you are sad c. increased respiration rate when your muscles need more oxygen d. increased heart rate when your lungs need more oxygen