The barter economy is an example of what kind of economy?

On venus, which of the following drives geological change? a. hurricanes b. volcanoes c. tsunamis d. earthquakes

Which ofbthe following is a characteristic shared by both brazil and mexico

Which revelation resulted from the observation of the spectrum of different galaxies? a. there were more galaxies whose spectrum was blueshifted b. there were no galaxies whose spectrum was redshifted c. there were more galaxies whose spectrum was redshifted d. there were no galaxies whose spectrum was blueshifted