What do you understand by saturated solution and unsaturated solution

A saturated solution is made by dissolving as much solute as possible in a solute. For example, add table sugar (solute) to a glass of water (solvent) until no more sugar will dissolve even with vigorous stirring. The undissolved sugar settles to the bottom of the glass.

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d.) circle motion requires a force to give it a centripetal acceleration.

the answer to this question is 3.