Explanation/Reference:
Preventive/Technical controls are also known as logical controls and can be built into the operating system, be software applications, or can be supplemental hardware/software units.
Source: KRUTZ, Ronald L. & VINES, Russel D., The CISSP Prep Guide: Mastering the Ten Domains of Computer Security, 2001, John Wiley & Sons, Page 34.

Explanation/Reference:
A Public Key Infrastructure (PKI) provides confidentiality, access control, integrity, authentication and non- repudiation.
It does not provide reliability services.
Reference(s) used for this question:
TIPTON, Hal, (ISC)2, Introduction to the CISSP Exam presentation.

Section: Access Control
Explanation/Reference:
The matrix lists the users, groups and roles down the left side and the resources and functions across the top.
The cells of the matrix can either indicate that access is allowed or indicate the type of access. CBK pp 317 -
318.
AIO3, p. 169 describes it as a table if subjects and objects specifying the access rights a certain subject possesses pertaining to specific objects.
In either case, the matrix is a way of analyzing the access control needed by a population of subjects to a population of objects. This access control can be applied using rules, ACL's, capability tables, etc.
"A capacity table" is incorrect.
This answer is a trap for the unwary -- it sounds a little like "capability table" but is just there to distract you.
"An access control list" is incorrect.
"It [ACL] specifies a list of users [subjects] who are allowed access to each object" CBK, p. 188 Access control lists (ACL) could be used to implement the rules identified by an access control matrix but is different from the matrix itself.
"A capability table" is incorrect.
"Capability tables are used to track, manage and apply controls based on the object and rights, or capabilities of a subject. For example, a table identifies the object, specifies access rights allowed for a subject, and permits access based on the user's posession of a capability (or ticket) for the object." CBK, pp. 191-192. To put it another way, as noted in AIO3 on p. 169, "A capabiltiy table is different from an ACL because the subject is bound to the capability table, whereas the object is bound to the ACL." Again, a capability table could be used to implement the rules identified by an access control matrix but is different from the matrix itself.
References:
CBK pp. 191-192, 317-318
AIO3, p. 169

A sag is a momentary low voltage. A spike is a momentary high voltage. A fault is a momentary power out and a brownout is a prolonged power supply that is below normal voltage. Source: HARRIS, Shon, All-In-One CISSP Certification Exam Guide, McGraw-Hill/Osborne, 2002, chapter 6: Physical security (page 299)

Explanation/Reference:
Packeting filtering firewalls are devices that enforce administrative security policies by filtering incoming traffic as well as outgoing traffic based on rules that can include the source and/or destination addresses.
"Outgoing data packets" is incorrect. Firewalls filter incoming as well as outgoing traffic. This is sometimes called Egress and Ingress filtering.
"Incoming data packets only" is incorrect. (see previous explantion)
"User data packet" is incorrect. A packet filtering firewall does not typicallly look into the data portion of the packet.
References
CBK, p. 464
AIO3, pp. 482 - 484