It's difficult to say definitively which process is dominant in shaping landscapes because it depends on the specific location and timescale we're considering. Different processes play significant roles at different scales and over different timeframes.

However, we can say that tectonic activity is a fundamental force that drives many other processes that shape landscapes.

Here's a breakdown:

* Tectonics: The movement of Earth's tectonic plates creates mountains, volcanoes, valleys, and ocean basins. This process, while slow, is fundamental and sets the stage for other shaping processes.

* Weathering: The breakdown of rocks and minerals by physical and chemical forces, such as wind, rain, ice, and temperature changes, creates soil, sediment, and changes the form of existing landforms.

* Erosion: The transportation of weathered material by wind, water, ice, and gravity shapes hills, valleys, canyons, and river systems.

* Deposition: The process of dropping off eroded material in new locations, creating landforms like deltas, beaches, and sand dunes.

* Climate: Climate plays a significant role in influencing weathering and erosion rates, leading to different landscapes in different regions. For example, deserts often feature wind-blown sand dunes, while areas with heavy rainfall may develop deep canyons.

* Biological processes: Plants, animals, and microorganisms can also contribute to landscape change through processes like soil formation, plant root growth, and the creation of burrows and nests.

In conclusion: While tectonic activity is a driving force, a combination of these processes constantly interacts, shaping and reshaping landscapes over vast time scales.