\[
\begin{array}{|c|c|}
\hline \text{measurement} & \text{number of significant digits} \\
\hline 3.2 \times 10^{-2} \, \text{mL} & \boxed{2} \\
\hline -6.0 \times 10^{-3} \, \text{kJ/mol} & \boxed{2} \\
\hline 43600 \, \text{kg} & \boxed{3} \\
\hline
\end{array}
\]