Final answer:
The two examples of mixtures given in the provided options are air, which is a homogeneous mixture of gases, and gelatin, which is a heterogeneous mixture or colloid. Therefore, the correct answer is d. air; gelatin.
Step-by-step explanation:
The question is asking to provide two examples of mixtures from the given options. Mixtures are combinations of two or more substances where each substance maintains its own chemical properties. The mixtures can be classified into homogeneous mixtures, where the composition is uniform and appears the same throughout, and heterogeneous mixtures, where the composition is not uniform and the substances can often be seen distinctly.
Looking at the choices provided and understanding what constitutes a mixture:
- Lemonade is a solution (homogeneous mixture) of water, sugar, and lemon juice.
- Salt water is a homogeneous mixture or solution of salt dissolved in water.
- Salad dressing often includes oil and vinegar, which do not completely mix, making it a heterogeneous mixture.
- Air is a homogeneous mixture of gases like nitrogen, oxygen, and carbon dioxide.
- Gelatin, especially before it sets, is considered a colloid, which is a type of heterogeneous mixture.
Therefore, the correct answer, providing two examples of mixtures, is d. air; gelatin.