Item WE014004: Wind, water, and the growth of plant roots can wear away the solid rock of a valley.
Which of the following can break the rock layer that makes up the sides of a valley so that the valley becomes wider?
   
- Wind, water, and the roots of plants can break the rock layer.
- Water and wind can break the rock layer, but the roots of plants cannot.
- Water can break the rock layer, but wind and the roots of plants cannot.
- Neither wind, water, nor the roots of plants can break the rock layer.
| Answer Choice | Overall | Grades | Gender | Primary Language | ||||
|---|---|---|---|---|---|---|---|---|
| n = 2530 | 6–8 n = 1530 | 9–12 n = 990 | Male n = 1225 | Female n = 1262 | English n = 2232 | Other n = 226 | ||
| A. | Wind, water, and the roots of plants can break the rock layer. | 52% | 49% | 56% | 51% | 52% | 52% | 45% | 
| B. | Water and wind can break the rock layer, but the roots of plants cannot. | 27% | 28% | 25% | 25% | 29% | 27% | 28% | 
| C. | Water can break the rock layer, but wind and the roots of plants cannot. | 15% | 16% | 13% | 17% | 12% | 14% | 18% | 
| D. | Neither wind, water, nor the roots of plants can break the rock layer. | 7% | 7% | 7% | 7% | 7% | 7% | 9% | 

