21. Which type of rock is formed by the compaction and cementation of plant and animal remains?
a) Igneous rock
b) Sedimentary rock
c) Metamorphic rock
d) None of the above
22. Which type of rock is formed by the alteration of existing rocks through heat and pressure?
a) Igneous rock
b) Sedimentary rock
c) Metamorphic rock
d) None of the above
23. What is the name of the process that moves material downhill due to gravity?
a) Erosion
b) Deposition
c) Weathering
d) Sedimentation
24. Which type of rock is formed by the solidification of magma or lava?
a) Igneous rock
b) Sedimentary rock
c) Metamorphic rock
d) None of the above
25. What is the name of the process that forms sand dunes?
a) Erosion
b) Weathering
c) Deposition
d) Sedimentation
