Geomorphology is the science that studies the origin and development of landforms (such as hills, valleys, sand dunes, caves), and how those landforms combine to form landscapes. As such, it makes a critical contribution to answering the sorts of aforementioned questions. Geomorphological studies include the quantitative analysis of landform shapes, the monitoring of surface and near-surface processes (e.g. running water, ice, wind) that shape landforms, and the characterisation of landform changes that occur in response to factors such as tectonic and volcanic activity, climate and sea level change, and human activities. Investigations may be directed principally towards reconstructing past processes and landform changes, towards understanding present-day processes and landform changes, or towards anticipating future processes and landform changes.