What financial concept allows an individual to accumulate a significant amount of money over time through regular savings?

The correct answer highlights the power of compound interest, which enables an individual to grow their savings significantly over time. Unlike simple interest, which is calculated only on the principal amount, compound interest is calculated on the initial principal and also on the accumulated interest from previous periods. This means that as the amount of interest increases, the base on which future interest is calculated also expands, leading to a snowball effect of growth.

Essentially, the more frequently the interest is compounded—such as annually, semi-annually, or monthly—the more effective this growth becomes, enabling savers to build wealth more rapidly as their money earns interest on interest. This principle is fundamental in finance and investing, promoting the importance of starting to save early to maximize the effects of compounding over time.