Difference between basic and acidic lava

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

Describe the four major spheres of the earth system; identify the parts of the earth they each represent. explain what is meant by the "earth system."

Using plate tectonics and elastic rebound theory, describe why juan de fuca plate subduction produces so few earthquakes. what will happen in the future?