<u>Answer:</u>
<em>The measurement 100.5 mL has 4 significant figures.</em>
<u>Explanation:</u>
Significant figures are defined as the digits that provides information in order to maintain accuracy and precision of a measurement. <em>Any nonzero number, trailing zeros with a decimal point and zeros between two numbers are recognizes as significant digits. </em>
Whereas, the figures which do not contribute to sustain the accuracy and precision of the measurement are insignificant figures.
<em>The leading zeros in any digit and the trailing zeros without decimal are considered as insignificant figures. </em>
<em>As in 100.5 1, two zeros and 5 after a decimal is significant figure which are 4 in total.</em>