Answer:
Low Viscosity magma
Explanation:
Low viscosity magma is usually thinner in comparison to the high viscosity magma and comprised of relatively lesser amount of dissolved gases. They move easily without any obstruction at a faster rate. When any volcanic eruption occurs where there is low viscosity magma, it allows the magma to move in thin layers and rapidly and quietly.
Thus, a shield volcano is comprised of a broad, non steeper sides with low viscous magma.
