Answer: Option [B]A hole in Earth's crust through which magma comes to Earth's surface is known as Vent. A volcano is a vent in the Earth's crust through which molten material under the Earth erupts suddenly.
Answer: Option [C]Layers of volcanic materials that build up around vent to form a cone-shaped structure are known as Cone. Cone is the structure of the volcano formed as a heap of cooled materials that come out of volcanic eruptions
Answer: Option [A]Fluidity of lava is determined by amount of silica.
Answer: Option [D]Top of magma is forced onto Earth's surface is known as Crater.
Answer: Option [C]Volcanoes that have erupted in historic times and are still likely to erupt, are known as Dormant volcanoes. Volcanoes are classified as active, dormant, or extinct. Active volcanoes have a recent history of eruptions; they are likely to erupt again. Dormant volcanoes have not erupted for a very long time but may erupt at a future time. Extinct volcanoes are not expected to erupt in the future.