1 Vague definition.
The idea that it (any one of the following is sufficient):
- is essential facilities (capital) and services such as roads, airports, sewage treatment, water systems, railways, telephone and utilities
- reduces the cost / increases efficiency of economic activity
- is usually supplied by the government
- is necessary for economic activity.
2 Accurate definition.
An explanation that it (any two of the following is sufficient):
- is essential facilities (capital) and services such as roads, airports, sewage treatment, water systems, railways, telephone and utilities
- reduces the cost / increases efficiency of economic activity
- is usually supplied by the government
- is necessary for economic activity.