Can you please give me a genuine answer and not something from the internet please so that i can get a clear understanding

This question is about computer networks. explain the following terms relating to networking stacks: layer, protocol, service. Give an example of each. what are the main layers in the TCP/IP reference model? Summarize their functionality in one sentence each explain the main functionality of the Network Layer in the TCP/IP reference model. This should include a description of IP addresses, datagrams, and routing.