if you add sugar to water and the sugar no longer dissolves and it settles at the bottom the solution has become

It forms a solution.

Explanation:

A pure substance is when only one type of atom or molecule is present. In this case the substance contains two different molecules; sugar and water, assuming sugar is all one type (e.g. glucose) and there are no contaminants in the water or sugar before combining the two.

Dissolving the sugar in the water makes a homogeneous mixture and once dissolved a solution is made by the combination of a solute (sugar) and solvent (water).

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plants need sunlight, water, and carbon dioxide to make food. plants use the raw materials of water, nutrients they absorb from soil, and carbon dioxide to make sugars the plant can use. energy from the sun and chlorophyll are also needed.