Question

________ floods a computer with requests until it shuts down and refuses to answer any requests for information.

Answer 1

a DDOS attack floods a computer with requests until it shuts down and refuses to answer any requests for information

Answer 2

Denial Of Service attack or DoS attack floods a computer with requests until it shuts down and refuses to answer any requests for information.

It is known as Denial of Service attacks because DoS attack renders the victim host useless to any other node on the network or outside the network.  

Denial of Service attack can also be modified/upgraded in the form of Distributed Denial of Service attacks in which multiple hosts target the same host by flooding it with requests.