Final answer:
Private markets fail to provide public goods that have no exclusion and no rivalry, due to the characteristics of non-excludability and non-rivalry.
Step-by-step explanation:
When a good has no exclusion and no rivalry, it is considered a public good. Public goods are goods that are difficult for market producers to sell to individual consumers because they have the characteristics of non-excludability and non-rivalry. Non-excludability means that it is difficult to exclude people from using the good, even if they do not contribute to paying for its creation. Non-rivalry means that one additional user does not diminish the value of the good for other users.
For example, consider a public park. It is difficult to exclude people from using the park, and one person enjoying the park does not diminish its value for others. Therefore, private markets fail to provide public goods like parks, because there is no means to profit from their production.