Which two of the following sentences from the
article include central ideas of the article?
1. Over long periods of time -
millions and millions of years
- all rocks play a part in
Earth's recycling system
2. Magma that intrudes or
pushes itself into layers and
cracks of existing rocks
underground forms intrusive
igneous rocks, like granite.
3. The only parts of the rock
cycle that we can easily
observe are the surface
processes that break down
rocks, called erosion, and
that build up rocks, called
deposition.
4. There are many types of
landslides, but they all
involve large amounts of
moving rocks