How are each of the following performed: (a)denial of service (DOS) attack
(b)distributed denial of service (DDOS) attack
(c) domain name service (DNS) attack
How are each these attacks (a, b,c, d above) stopped or mitigated?

none because it's so obvious

a study funded by private corporations refuting global warming

the today function returns a valid value without any arguments.

the today function returns the current date based on the computer's date setting and formatted as a date. today takes no parameters, but requires that you use empty parentheses