What does the term "significant figures" specify?

The term "significant figures" is crucial in understanding the accuracy and precision of numerical data, particularly in scientific and engineering contexts. Significant figures specify which digits in a number carry meaningful information about its precision. This includes all non-zero digits, any zeros between significant digits, and any trailing zeros in a decimal portion, but it does not count leading zeros, as they do not contribute to the value of the number.

Choosing the option that highlights the required number of digits not including leading zeroes captures the essence of what makes a digit significant in terms of measuring and representing values. Leading zeros are merely placeholders and do not indicate the precision or accuracy of the measurement itself, which is why they are not included in the count of significant figures.

In contrast, the other choices either lack specificity or misrepresent the concept. The total number of digits does not consider which ones are meaningful, while the precision of measurements relates more broadly to how detailed a measurement is rather than being strictly about significant figures. The range of acceptable values, though relevant in certain contexts, does not define the concept of significant figures directly, which focuses on the representation of specific digits in a number.