What best describes these two molecules? They are not isomers. They are structural isomers. They are geometric isomers. They are both structural and geometric isomers.

Step 1: Understand the moleculesThe first molecule is CBr4, which means it has one carbon atom and four bromine atoms. The second molecule is CH3Br, which means it has one carbon atom, three hydrogen atoms, and one bromine atom.Step 2: Understand the types of isomersIsomers are molecules that have the same molecular formula but different structural or spatial arrangements. Structural isomers have the same molecular formula but different bonding patterns and atomic organization. Geometric isomers are molecules that have the same molecular formula and the same bonding patterns but different spatial positioning.Step 3: Compare the moleculesComparing the two molecules, we can see that they have different molecular formulas (CBr4 vs CH3Br), so they cannot be isomers of any kind.Answer: The best description for these two molecules is that they are not isomers.