Final answer:
The method used for obtaining materials or services unavailable in the supply system includes interlibrary loans and purchasing from alternative marketplaces to address scarcity.
Step-by-step explanation:
When materials or services are not available in the supply system, individuals and organizations typically turn to alternative methods such as interlibrary loans, purchasing from marketplaces, or finding new outlets for necessary goods. For example, in the case of academic resources that are not available in a library's collection, one can obtain these materials through an interlibrary loan system where libraries borrow materials from one another on behalf of their patrons. In a broader economic context, when faced with the problem of scarcity, people acquire the items they need, such as food, shelter, and healthcare, by purchasing them. To finance these purchases, individuals work for pay or rely on others who do so, addressing scarcity through economic exchange.