Classifying goods and resources: goods, services, and resources differ in the extent to which people can be excluded from consuming them and in the extent to which one person"s consumption rivals the consumption of others. Excludable: excludable: a good is excludable if it is possible to prevent someone from enjoying its benefits. Brinks security services, a concert: nonexcludable: a good is nonexcludable if it is impossible (or extremely costly) to prevent anyone from benefiting from it. Rival: rival: a good is rival if one person"s use of it decreases the quantity available for someone else. A brinks security truck can"t deliver cash to two person"s houses at the same time: nonrival: a good is nonrival if one person"s use of it does not decrease the quantity available for someone else. A can of coke: public goods. Ocean fish: natural monopolies more firms can. A producer who can serve the entire market at a lower cost than two or.