Of all the fresh water on Earth, water in lakes (large and small) and rivers accounts for the largest proportion. 

Aquicludes are porous rock or sediment layers that readily provide water for human use.

If there is no water, there is no chemical weathering.

Drainage basin, watershed and catchment of a river all refer to the same area that can be defined (demarcated) by the mountain ridges (ridgelines) surrounding all tributaries of a river.

Runoff is the general term that all types of water on the earth surface, including sheet flow and channeled flow.

Gravity is a must (required) for mass movement, and the presence of water is not necessary. 

The world ocean covers what percentage of Earth’s surface?

Which two processes form most sinkholes?

The zone of aeration:

Pebbles and cobbles would most likely be transported by a river as: