Answer:
The correct answer is: B. Mass-movement zones are difficult to predict.
Step-by-step explanation:
Mass movement is the downslope movement of earth materials under the influence of gravity. It can occur on both gentle and steep slopes, and can be triggered by a variety of factors, including earthquakes, heavy rains, and human activity. Mass-movement zones are areas that are particularly susceptible to mass movement, and can be difficult to predict. This is because they are often located in areas with steep slopes, loose soil, and abundant rainfall.
A. It becomes possible when strong, intact rock gets weathered.
This is not true. Mass movement can occur on both strong and weak rocks. In fact, strong rocks are often more susceptible to mass movement because they are more likely to fracture and break apart.
C. It happens when joints and faults are oriented perpendicular to slopes.
This is not always true. Joints and faults can be oriented in any direction, and do not always cause mass movement. However, they can make slopes more unstable and more susceptible to mass movement.
D. It occurs when downslope force equals resistance force.
This is not true. Mass movement occurs when the downslope force exceeds the resistance force. This can happen when the slope is steep, the soil is loose, or there is a lot of water in the soil.