From Shon Harris AIO Fifth Edition:
Protecting power can be done in three ways: through UPSs, power line conditioners, and backup sources.
UPSs use battery packs that range in size and capacity. A UPS can be online or standby.
Online UPS systems use AC line voltage to charge a bank of batteries. When in use, the UPS has an inverter that changes the DC output from the batteries into the required AC form and that regulates the voltage as it powers computer devices.
Online UPS systems have the normal primary power passing through them day in and day out. They constantly provide power from their own inverters, even when the electric power is in proper use. Since the environment's electricity passes through this type of UPS all the time, the UPS device is able to quickly detect when a power failure takes place. An online UPS can provide the necessary electricity and picks up the load after a power failure much more quickly than a standby UPS.
Standby UPS devices stay inactive until a power line fails. The system has sensors that detect a power failure, and the load is switched to the battery pack. The switch to the battery pack is what causes the small delay in electricity being provided. So an online UPS picks up the load much more quickly than a standby UPS, but costs more of course.

Section: Network and Telecommunications
Explanation/Reference:
The main responsibility of the network layer is to insert information into the packet's header so that it can be properly routed. The protocols at the network layer must determine the best path for the packet to take.
The following answers are incorrect:
Session layer. The session layer is responsible for establishing a connection between two applications.
Physical layer. The physical layer if responsible for converting electronic impulses into bits and vice-versa.
Transport layer. The transport layer is responsible for data transmission and error detection.
The following reference(s) were/was used to create this question:
Source: HARRIS, Shon, All-In-One CISSP Certification Exam Guide, McGraw-Hill/Osborne, v3, chapter 7:
Telecommunications and Network Security (page 422-428).
ISC2 Official ISC2 Guide to the CBK (OIG) 2007, p. 409-412

Section: Security Operation Adimnistration
Explanation/Reference:
The operation phase of an IT system is concerned with user authentication.
Authentication is the process where a system establishes the validity of a transmission, message, or a means of verifying the eligibility of an individual, process, or machine to carry out a desired action, thereby ensuring that security is not compromised by an untrusted source.
It is essential that adequate authentication be achieved in order to implement security policies and achieve security goals. Additionally, level of trust is always an issue when dealing with cross-domain interactions. The solution is to establish an authentication policy and apply it to cross-domain interactions as required.
Source: STONEBURNER, Gary & al, National Institute of Standards and Technology (NIST), NIST Special Publication 800-27, Engineering Principles for Information Technology Security (A Baseline for Achieving Security), June 2001 (page 15).

Section: Security Operation Adimnistration
Explanation/Reference:
The software plans and requirements phase addresses threats, vulnerabilities, security requirements, reasonable care, due diligence, legal liabilities, cost/benefit analysis, level of protection desired, test plans.
Implementation is incorrect because it deals with Installing security software, running the system, acceptance testing, security software testing, and complete documentation certification and accreditation (where necessary).
System Feasibility is incorrect because it deals with information security policy, standards, legal issues, and the early validation of concepts.
Product design is incorrect because it deals with incorporating security specifications, adjusting test plans and data, determining access controls, design documentation, evaluating encryption options, and verification.
Sources:
KRUTZ, Ronald L. & VINES, Russel D., The CISSP Prep Guide: Mastering the Ten Domains of Computer Security, John Wiley & Sons, 2001, Chapter 7: Applications and Systems Development (page 252).
KRUTZ, Ronald & VINES, Russel, The CISSP Prep Guide: Gold Edition, Wiley Publishing Inc., 2003, Chapter
7: Security Life Cycle Components, Figure 7.5 (page 346).

These are core functions of the incident response process.
"Incident Evaluation" is incorrect. Evaluation of the extent and cause of the incident is a component of the incident response process.
"Incident Recognition" is incorrect. Recognition that an incident has occurred is the precursor to the initiation of the incident response process.
"Incident Protection" is incorrect. This is an almost-right-sounding nonsense answer to distract the unwary.
References CBK, pp. 698 - 703