Final answer:
Both rust forming on a bicycle frame and mixing lettuce and salad dressing involve chemical reactions, where new substances with different properties are produced. The correct answer is (1) They both involve chemical reactions.
Step-by-step explanation:
What mixing lettuce and salad dressing and rust forming on a bicycle frame have in common is that they both involve chemical reactions. In the case of rust formation, iron is exposed to water and oxygen, resulting in a chemical change where the iron, oxygen, and water react to form a new substance, rust. The mixing of lettuce and salad dressing involves various ingredients reacting and potentially changing their properties, although this is a simpler process compared to rusting. In contrast to a physical change, which does not alter the molecular structure of the substances involved, a chemical change transforms one molecular substance into another, producing new matter with different properties.
For your specific question, the correct answer is (1) They both involve chemical reactions. Both the process of rusting and the combination of ingredients in salad dressing are examples of these transformations at the molecular level. Rust is a product of an oxidation-reduction reaction, which is a specific type of chemical reaction, and mixing salad dressing may involve emulsification, which is a change in the state of the substances involved.