Q1: The shearing force acting along the slice of a curved surface of slippage, causes the soil to slide

ANS:A - down at the centre

"down at the centre" in the context of slope failure does not accurately describe the typical behavior of soil slippage. It was an incorrect description, and I appreciate your patience. In slope failure scenarios, when a shearing force acts along the slice of a curved surface, the soil tends to move in a downward and outward direction, especially at the toe of the slope. This downward movement occurs due to the gravitational forces acting on the soil mass and the loss of shear strength along the failure surface. Therefore, "downward at the toe" is the more accurate description of the behavior typically observed in slope failure scenarios, where the soil mass slides and moves downward and outward at the lower part or toe of the slope.