Blocking access to a facility computer system by unauthorized user is accomplished through use of

Since you provide no options, There are 2 ways of blocking access to a facility computer user by unauthorized user. If you want to block the unauthorized user who could get an access to it from inside facility, you could use a Password.  If you want to block unauthorized hackers to hack in your system, you use a Firewall

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True because all jobs are different and they all have chemicals that are for cleaning

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