Desalination is the most expensive way of delivering spring water ocean water rain water freshwater

Freshwater

Explanation:

Desalination is a process by which salt is removed from sea or brackish water. Desalination plants are industrial facilities intended for desalination, generally of seawater or salty lakes for the purpose of obtaining potable water.

Seawater is very salty because it has dissolved mineral salts that precipitate when water evaporates. Due to the presence of these mineral salts, seawater is not potable for humans and its ingestion in large quantities can lead to death. 97.5% of the water that exists on our planet is salty and only an amount less than 1% is suitable for human consumption. Getting water from the sea is one of the possible solutions to the shortage of drinking water. By desalination of seawater, fresh water suitable for supply and irrigation is obtained. Seawater desalination plants have produced drinking water for many years, but the process was very expensive and until relatively recently they have only been used in extreme conditions. There is currently a production of more than 24 million daily cubic meters of desalinated water worldwide, which means the supply of more than 100 million people.

Desalination plants also have drawbacks. In the process of salt extraction, saline residues and pollutants are produced that can harm flora and fauna. In addition, they represent a high cost of electricity consumption. In order to avoid this, studies are currently being carried out to build more competitive, less polluting desalination plants that use renewable energy sources.

d. stage 4

explanation:

the existence of some kind of demographic transition is widely accepted in the social sciences because of the well-established historical correlation linking dropping fertility to social and economic development.[1] scholars debate whether industrialization and higher incomes lead to lower population, or whether lower populations lead to industrialization and higher incomes. scholars also debate to what extent various proposed and sometimes inter-related factors such as higher per capita income,lower mortality, old-age security, and rise of demand for human capital are involved.[2]

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