No fossil fuels are renewable forms of energy.
Some combustible gases are fossil fuels.
Therefore, some combustible gases are not renewable forms of energy.

Use Venn diagrams to determine whether the following standard-form categorical syllogisms are valid from the Boolean standpoint, valid from the Aristotelian standpoint, or invalid. Then, identify the mood and figure, and cross-check your answers with the tables of valid syllogisms found in Section 5.1.