Dear sir,I need the answer of two questions below.Fetchingso

Dear sir,I need the answer of two questions below.Fetchingsomething over the network is both slow and expensive. Large responsesrequire many roundtrips between the client and server, which delays whenthey are available and when the browser can process them, and alsoincurs data costs for the visitor. As a result, the ability to cache andreuse previously fetched resources is a critical aspect of optimizingfor performance.The good news is that every browser ships with an implementation of an HTTP cache.Examplain in details the follwoing: Validating cached responsesCache-Control and Cache-Control policy