Answer: Liquids have the following characteristics: no definite shape (takes the shape of its container) has definite volume. particles are free to move over each other, but are still attracted to each other. liquids have lesser densities than solids. Intermolecular forces of attraction is weaker than solids. They have considerable space between the particles. Liquids flow from higher to lower level. Liquids have their boiling points above room temperature, under normal conditions.
I gave many characteristics
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Well where is the elements and category
The answer of this question is Oxygen
I think c is used in electric power plants.
The answer should be B, it reacts in air to form a green layer.
Chemical properties means that how the substance that reacts with other substance to produce new substances. Usually it cannot be measured or observed just with the substance itself.
From all the options above, only B is a reaction. The green layer formed is a new substance produced by copper and air. It involves a chemical change.
Other options like boiling points or state of matter, these are physical properties. They do not require it to react to other substances and the can be measured and observed easily.