A Level Biology Practice Exam

What constitutes significant figures in a number?

1. The total number of digits in the number

2. The digits that have meaning and contribute to precision

3. Only the whole number parts

4. Digits including trailing zeros after the decimal

The correct answer is: The digits that have meaning and contribute to precision

Significant figures are important in scientific measurements as they indicate the precision of the data. The digits that are considered significant are those that contribute meaningfully to the value of the number—this includes all non-zero digits, any zeros between non-zero digits, and trailing zeros in the decimal portion of the number. This concept helps ensure that scientific communication is clear regarding the certainty of measurements. When determining significant figures, it's essential to recognize that not all digits hold the same weight in describing accuracy. Non-numeric placeholders (like leading zeros or zeros at the end of a whole number without a decimal) do not contribute to the precision of a measurement, thus distinguishing them from the meaningful digits that comprise significant figures.