Tectonic plate margins are described as places where which processes occur?

• A. Plates are stationary and do not interact.
• B. Plates are moving but with no built-up pressure.
• C. Plates are moving and enormous pressures are built up and released.
• D. Only oceanic crust exists.

Answer: (C)

At plate margins, the key idea is that the plates are in contact and moving relative to each other. This motion causes them to rub, stick, and drag, so stress builds up in the rocks. When that stress is released suddenly, energy propagates as seismic waves, causing earthquakes. Margins are also zones where magma can rise and produce volcanoes or where rocks are pushed together to form mountains, due to subduction or collision. So plates are moving and enormous pressures are built up and released, which is why earthquakes and related volcanic or mountain-building processes occur there. The other statements don’t fit because margins aren’t static or non-interacting, and crust at margins isn’t limited to oceanic alone.