Which of the following best describes the features that can be produced in a limestone environment?

In a limestone environment, the processes of weathering and erosion play a significant role, particularly through the action of water. This leads to the formation of unique geological features that are characteristic of karst landscapes. Arches and stacks are formations that can occur as a result of the dissolution of limestone, where water seeps through cracks and hollows out caves. Over time, as the limestone continues to erode, structures like arches can form when sections of the rock are left standing while the surrounding material has eroded away. Stacks are similar formations that can arise when coastal erosion affects limestone cliffs, leading to isolated towers of rock being left standing.

Mountains and valleys, flat plains and hills, as well as deserts and canyons, can arise in different geologic contexts but do not specifically reflect the unique dissolution and erosion processes associated with limestone. Therefore, the emergence of arches and stacks specifically highlights the distinctive features typical of a limestone environment.