Final answer:
The statement that the largest river systems in the world are permanent features on the landscape is false. Rivers change over time due to natural processes and human activities, with features like floodplains and oxbow lakes illustrating their dynamic nature.
Step-by-step explanation:
Geologically speaking, the largest river systems in the world are not permanent features on the landscape; instead, they are dynamic and ever-changing due to geological and climatic factors. River systems are influenced by processes such as erosion, sedimentation, flooding, and human activities which can alter their course and characteristics over time. For example, the Tigris and Euphrates rivers have seen significant changes in their courses over the millennia due to periodic flooding. Similarly, the vibrant ecosystem of an oxbow lake can represent a past meander of a river that has been cut off from the main channel.
Regarding some of the common features associated with a river system, they include the floodplain, which is the flat area beside the river that gets flooded when the river overflows. Other features are levees which are raised banks formed by the accumulation of sediments during floods, cut banks and point bars which indicate erosion and deposition on the sides of the river, and thalweg, the line of the deepest water in a river channel.
Answering whether the largest river systems in the world are permanent features on the landscape, the correct choice would be:
false