FEMArecommends that water treatment products sold in camping
or surplus stores should not be used, unless the only active ingredient is 5.25 percent hypochloritE. When adding liquid bleach, it should contain 5.25 percent hypochlorite and no other added cleaners or scents. Distilling the water is the most highly recommended method,
as it also removes other chemicals and heavy metals, as well as most
microbes. Source: Emergency Water and Food Procedures, Federal Emergency
Management Agency, April, 1997.

Firewall rules can be used to enable access for traffic to specific ports or services. "Service numbers" is rather stilted English but you may encounter these types of wordings on the actual exam -- don't let them confuse you.
"Only unauthorized application port or service numbers" is incorrect. Unauthorized ports/services would be blocked in a properly installed firewall rather than permitting access.
"Only authorized application port or ex-service numbers" is incorrect. "Ex-service" numbers is a nonsense term meant to distract you.
"Only authorized application port or service integers." While service numbers are in fact integers, the more usual (and therefore better) answer is either service or "service number."
References
CBK, p. 464
AIO3, pp. 482 - 484

Section: Security Operations

Section: Mixed questions