The factors that help create volcanoes from the list provided are:
- plate tectonics: The movement of tectonic plates can lead to volcanic activity, especially at convergent and divergent boundaries.
- built up magma: Accumulation of magma beneath the Earth’s surface can lead to the formation of volcanoes when pressure builds and causes an eruption.
- cracks in Earth's crust: Cracks or fissures can allow magma to escape and lead to volcanic activity.
Landslides do not help create volcanoes; rather, they are a result of volcanic eruptions (when material collapses down the side of a volcano).
So, the applicable answers are:
- plate tectonics
- built up magma
- cracks in Earth's crust