The foam is formed by trapping gas bubbles in a liquid or solid substance. In the context of the question, whipped cream and marshmallows are examples of foams because they consist of air bubbles dispersed in a solid or liquid.
1. Whipped cream is a foam because air is incorporated into the cream while beating it, creating a light and airy texture.
2. Marshmallows are also considered foams as they are made by whipping a mixture of sugar, water, and gelatin to incorporate air and create a fluffy, spongy texture.
Therefore, the correct answer to the question "Which of the following is a foam?" would be options a (whipped cream) and c (marshmallows).
