How do public networks differ from private networks?

Public networks are characterized by their open accessibility, allowing anyone to connect without the need for authentication or special permissions. This openness makes public networks widely available for activities like browsing the internet in cafes or connecting to Wi-Fi in public parks. In contrast, private networks are designed with restricted access, often requiring a specific login or connection procedure, which helps to maintain security and control over the network and its resources. This distinction is fundamental to understanding how different types of networks function and are utilized in various contexts, from home and office environments to public spaces.

The other options do not accurately capture the essence of how public and private networks differ. While speed can vary based on factors like network congestion and infrastructure, it is not an inherent characteristic distinguishing private from public networks. Firewalls provide security measures that can be found on both types of networks; thus, saying public networks are secured by firewalls doesn't reflect a difference. Additionally, while many private networks may have internet access, it is not accurate to claim that all private networks lack such access, as many are designed to connect to the internet while still restricting access to authorized users.