What encompasses all the area of a particular stream that contributes to water flow?

The correct answer is the drainage basin. A drainage basin, also known as a watershed, is the entire area from which water collects and flows into a particular stream. This includes all the precipitation and surface runoff that converges at the stream, contributing to its water flow.

This concept is crucial in understanding hydrology and water resource management, as it helps identify how land use, topography, soil types, and vegetation cover affect water flow and quality in the stream. A drainage basin is often outlined by ridges or high terrain that separates it from neighboring basins, making it a significant area for studying water distribution and ecological impacts within a landscape.

In contrast, stream load refers to the total amount of sediment and organic matter carried by a stream, which doesn't encompass the total area feeding the stream. Dissolved load describes the minerals and nutrients dissolved in the water that contribute to the stream's water chemistry but does not denote the area or topography involved. Bedload consists of larger particles that move along the bottom of a stream and is not representative of the broader area contributing to stream flow.