Which characteristic of cash ensures that it maintains its physical form over time?

The characteristic of cash that ensures it maintains its physical form over time is durability. This aspect refers to the ability of cash to withstand physical wear and tear, ensuring that it remains intact and usable for transactions over an extended period. Durable materials used in the production of currency, such as special paper and polymers, are designed to resist damage from handling and to survive environmental factors.

In contrast, while attributes like uniformity pertain to the consistency in the appearance and value of the currency, acceptability relates to the recognition and usage of cash as a medium of exchange within the economy. Portability addresses how easy it is to carry cash, but none of these characteristics specifically ensures that cash retains its physical form over time as effectively as durability does.