What is a client-server system? What are the main features

What is a client-server system? What are the main features of a client-server system? Describe the architecture of a client-server system. Adhere to MLA formatting and reference guidelines Deliverable length 3-5 pages 

While browsing around the WWW, identify, locate and describe a website which uses a 3 tier Architecture, discuss each layer of that website including how to query the website, and the type of database working on the website. Include additional features of the application interface to the website. Deliverable length 1-2 paragraphs.

 Why is SQL Data Access considered middleware? Explain the purpose of SQL Data Access. How does it differ from other types of middleware? Explain. 1-2 paragraphs