Concept:Basic lava is highly fluid and spreads over a wide area, building a broad, gently sloping volcanic mountain.
Explanation:Basic lava has low silica content and low viscosity.
This allows it to flow easily and travel long distances before cooling.
Repeated outpourings of such fluid lava build a low, dome-shaped volcano with gentle slopes.
This structure is called a shield volcano.
In contrast, cinder cones form from thick, explosive lava fragments, not fluid basic lava.
Answer:C. shield