Final answer:
A line extension involves introducing new variations within the same product line, while a product modification involves making changes to an existing product in terms of quality, functionality, or features.
Step-by-step explanation:
The primary distinction between a line extension and a product modification lies in the scope of the changes made to an existing product. A line extension refers to introducing new variations or versions of an existing product within the same product line, while a product modification involves making changes to an existing product in terms of quality, functionality, or features.
For example, if a company introduces a line extension for a shampoo brand by launching a new variation with added herbal extracts or a different fragrance, it stays within the existing product line. On the other hand, if the company decides to modify the shampoo formulation to make it more suitable for people with specific hair conditions, it would be considered a product modification.