Explain the definition of a variable in research methodology.

How is the introduction of the cane toad to queensland, australia an example of the unintended consequences of using non-native species to control pests? (site 1)

To what extent was the chinese exclusion act a turning point in american foreign policy

Which soil horizon, also known as the zone of accumulation, is enriched in clay, iron oxides, silica, carbonate, and other materials?