The right answer is water.
A solution is a liquid containing several constituents
* The majority constituent is called solvent. Most often consists of water, the solution is called aqueous solution.
* The substances in solution are called solutes.
* The species in solution are either molecules or ions.
If we add water in the aqueous solution, we will have a dilution. On the contrary, if we add solute or remove water (pure water in solutes) we will have a concentration.
<span>The delineation of an aquatic ecosystem is the process of spatial identification, mapping and recording of the site; description documents the critical components and processes that underpin the ecosystem values of the site, and develops conceptual model(s) and identifies threats.
Delineating an aquatic ecosystem often starts with defining the main aquatic elements (core elements). The core elements will often be distinct landforms or features such as a waterhole, a swamp, a lake or a river. Ecotonal areas may be included as part of the core element or may be considered as a separate zone. For example, riparian vegetation is often considered to be an integral part of a river ecosystem, even if only inundated in big flood events.
The area around the core elements that has a critical influence on ecosystem function is referred to here as the Ecological Focal Zone. Beyond this, the landscape may be usefully differentiated as a Zone of Influence and a Catchment Zone.</span>
It's A. Primary succession :) because Human economics and ecology are linked together because human economics utilizes the ecosystem and the natural resources in older for economics to actually exist. :)))))))