Final answer:
Water is the ingredient needed for frost wedging. This process occurs when water freezes and expands in cracks in rocks, causing them to break apart.
Step-by-step explanation:
The ingredient needed for frost wedging is water. Frost wedging is a process where water seeps into cracks in rocks, freezes, and expands, causing the rock to break apart. This process is especially effective in areas with freezing temperatures and abundant water sources, such as during winter in cold climates.
For example, during the winter, water can seep into cracks in a rock. When the temperature drops below freezing, the water freezes and expands, exerting pressure on the rock. Over time, this repeated freezing and expansion can cause the rock to fracture and break apart.