Which of the following metals can be extracted in its native state from the earth?GoldTinCopperMagnesium2Which of the following metals can be extracted from its ore by reduction with carbon?AluminiumPotassiumCopperMagnesium3Which method could be used to extract calcium from the earth?Mining as a native metalReduction by carbonElectrolysisOxidation by oxygen4Which of the following statements is true?Oxidation is the gain of oxygen and displacement is the loss of oxygenOxidation is the gain of oxygen and reduction is the loss of oxygenReduction is the gain of oxygen and oxidation is the loss of oxygenReduction is the gain of oxygen and displacement is the loss of oxygen5Which substance is reduced in the reaction: Zinc oxide + carbon → zinc + carbon dioxide?Carbon dioxideZinc oxideCarbonZinc

Gold can be extracted in its native state from the earth. This is because it is often found in its elemental form in nature, unlike most other metals which are usually found as ores.

Copper can be extracted from its ore by reduction with carbon. This is a common method used for metals that are less reactive than carbon, such as copper.

Calcium can be extracted from the earth through electrolysis. This is because calcium is a reactive metal, and reactive metals cannot be extracted from their ores by reduction with carbon.

The true statement is "Oxidation is the gain of oxygen and reduction is the loss of oxygen". This is the basic definition of these two terms in chemistry.

In the reaction: Zinc oxide + carbon → zinc + carbon dioxide, carbon is the substance that is reduced. This is because it gains oxygen to form carbon dioxide.