Question 3A response to an HTTP request than can be stored by the client and reused later without repeating the request again is called ... (single word)

The response you are looking for is called a "cache."

In the context of web communication, a cache is a mechanism that temporarily stores copies of responses from a web server. This enables the client (such as a web browser) to quickly access those resources without needing to resend requests for the same content repeatedly. Caching significantly improves the efficiency of data retrieval and reduces the load on web servers. The client checks its cache before making a new request; if a valid cached response is available, it can be reused. Hence, caching plays a vital role in enhancing the performance and speed of web applications.