A geographer is interested in studying how and why the environments of the Amazon Rainforest and the Andes Mountains are different. Which essential element of geography would the geographer use to complete this research? A. human systems
B. physical systems
C. places and regions
D. uses of geography

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