Final answer:
Faults are planar features where rocks slip past each other and are where earthquakes can occur. They are associated with plate tectonic boundaries but can also occur within plates and underwater. Plate tectonics is the key driver behind earthquake activity.
Step-by-step explanation:
Faults are geological fractures where rocks have slipped past each other. The answer to the student's question is: a. faults are planar features on which earthquakes occur.
Earthquakes are a phenomenon that occur due to the movement of tectonic plates at the Earth's surface. Plate boundaries, such as divergent, convergent, and transform, are often associated with seismic activity. While divergent and convergent boundaries can generate earthquakes through different mechanisms, transform boundaries are marked by the sliding of tectonic plates against each other along faults. This movement is not smooth and builds up stress, which is eventually released in the form of earthquakes.
Faults can occur at plate boundaries and also within plates, and they are not exclusive to any specific boundary type or environment, including underwater. Plate tectonics is the driving force behind the occurrence and distribution of earthquakes around the globe, influencing the location, depth, and magnitude of these seismic events.