Final answer:
Vinaigrette and mayonnaise are examples of an emulsion, which is a type of colloid where two immiscible liquids are combined with the help of an emulsifying agent, such as egg yolk in mayonnaise, that prevents the liquids from separating. The correct option is D.
Step-by-step explanation:
Vinaigrette and mayonnaise are examples of an emulsion. An emulsion is a type of colloid made by combining two immiscible liquids such as oil and vinegar. In the case of mayonnaise, oil and vinegar are blended together with egg yolks serving as the emulsifying agent.
Egg yolks contain substances that interact with both the oil and vinegar, allowing the mixture to become stable and preventing the liquids from separating. Similarly, vinaigrette requires an emulsifying agent to maintain dispersion. In general, an emulsion may be prepared by shaking or blending two immiscible liquids, which breaks one into droplets that disperse in the other.
In most emulsions, an emulsifying agent is necessary to keep the dispersed phase from coalescing and separating back into distinct layers. This is why mayonnaise and vinaigrettes don't separate into oil and vinegar layers once they've been properly mixed.
Therefore, the correct option is D.