Question

along the northwestern coast of the united states, the juan de fuca plate is being pushed underneath the north ame causing magma to rise to the surface. magma that reaches the surface and cools will often
a. erode a wide valley over time.
b. burn away a steep canyon.
c. cause a new tectonic plate to form.
d. build up a mountain over time.

Explanation:

When magma reaches the surface and cools, it solidifies into igneous rock. Over time, repeated eruptions and accumulation of this solidified rock build up landforms like mountains (e.g., the Cascade Range from this tectonic setting). Erosion (A) and canyon burning (B) are not caused by cooling magma. New tectonic plates (C) form at divergent boundaries, not from subduction-related magma cooling.

Answer:

D. build up a mountain over time.