It depends on HOW much money is circulating. If governments just print money with nothing to back it, hyperinflation occurs. If there's a bit too much money and credit, inflation happens. Generally, 3% inflation is considered normal and a healthy amount by economists.
The correct answer that would best complete the given statement above would be the word VIRUSES. Here is the complete statement. Viruses can only grow and multiply within the cells of another living thing, but they can remain active on a surface for several hours or days.