Final answer:
Public goods are nonexcludable and nonrivalrous, meaning their use by one person does not prevent use by others. Highways, airport security, and the provision of clean air and water are examples of public goods because they serve the public at large without excluding individuals and without one's use diminishing another's. Housing and employment, however, do not fall into the category of public goods.
Step-by-step explanation:
As you look at various government services, it's important to understand which are considered public goods. Public goods are defined by their nonexcludability and nonrivalry. Essentially, this means that once the good is provided, you cannot exclude people from using it, and one person's use does not reduce the availability for others. With this in mind, services such as highways, airport security, and the maintenance of clean air and water are considered public goods. These services are nonexcludable as they are available to all members of the public and nonrival in that one person's use does not diminish another's.
However, housing and employment are not typically classified as public goods. Housing is both excludable and rivalrous — you can prevent individuals from accessing a house, and one person's occupation of a house prevents another from using it. Employment is also not a public good, as a job position filled by one person is not available for another to occupy simultaneously.