Final answer:
Cliffs and valleys are often influenced by the position of master joints, which are significant structural features that can guide erosion and landscape formation. The interplay between geological structures and erosional processes shapes various topographic features.
Step-by-step explanation:
The location of features such as cliffs and valleys might be strongly influenced by the position of master joints. Master joints are significant structural features in the crust of the Earth, which can guide processes such as erosion and the formation of landscapes. For example, in the shaping of canyons on Mars, despite initially being tectonic cracks rather than the result of erosion by flowing water, water still played a role in shaping the canyons by seeping from deep springs and undercutting the cliffs. Similarly, on Earth, the presence of master joints can direct the flow of water or ice, potentially leading to erosion along those joints and the creation of valleys and other topographic features.
Erosion is a key force in landscape formation and can be influenced by various factors. For instance, water can accelerate erosion by contributing to over-steepened slopes or by saturating rock and soil, thus weakening them. Earthquakes can also make weak slopes fail, leading to changes in the landscape. Ultimately, the erosional features we see, whether on Earth or on celestial bodies like Mars, are often a combination of geological structures such as master joints and the erosional processes that act upon them.