Final answer:
Highways, airport security, and clean air and water are considered public goods because they are non-excludable and non-rivalrous. Housing and employment, while important, do not meet the criteria of public goods as they can be limited to certain individuals and can be used up by those individuals.
Step-by-step explanation:
Public goods are government services that are non-excludable and non-rivalrous, meaning they are available to all members of society and one person's use does not reduce availability to others. Identifying which of the listed government services are considered public goods is essential to understanding how these services benefit society as a whole.
Highways, airport security, and clean air and water are prime examples of public goods. Highways are used by everyone, and one person using it doesn't prevent others from doing so. Airport security is provided to ensure the safety of all passengers, with no individual able to be excluded from this service. Clean air and water are quintessential public goods that are critical for the health and well-being of every citizen, and they are not something that individuals can be prevented from accessing.
While housing and employment are important services, they are not strictly considered public goods because they can be both excludable and rivalrous. Housing can be restricted to certain people, and an increase in employment for one individual can potentially decrease the availability of jobs for others.