20. what are volcanic arcs typically associat...

20. what are volcanic arcs typically associated with? - a. divergent boundaries - b. transform boundaries - c. subduction zones - d. hot spots\nlearn 3.6: magma & intrusive activity\n21. what factors affect the formation of magma? - a. temperature, pressure, and water content - b. wind, rain, and erosion - c. sunlight, moonlight, and starlight - d. humidity, precipitation, and cloud cover\n22. which type of magma is characterized by high viscosity and high silica content? - a. basaltic magma - b. andesitic magma - c. rhyolitic magma - d. granitic magma\n23. what are plutons? - a. extrusive volcanic features - b. metamorphic rock layers - c. sedimentary rock formations - d. intrusive igneous rock bodies\n24. what is the term for volcanic rock fragments and ash ejected during eruptions? - a. pillow lava - b. tephra - c. pumice - d. scoria

Answer

# Answer: 20. C. Subduction zones 21. A. Temperature, pressure, and water content 22. C. Rhyolitic magma 23. D. Intrusive igneous rock bodies 24. B. Tephra # Brief Explanations: 20. Volcanic arcs form at subduction zones where one tectonic plate is forced beneath another. 21. Temperature, pressure, and water content are key factors in magma - formation. 22. Rhyolitic magma has high viscosity and high silica content. 23. Plutons are large intrusive igneous rock bodies. 24. Tephra is the general term for volcanic rock fragments and ash ejected during eruptions.