The proxy (application layer firewall, circuit level proxy, or application proxy ) is a second generation firewall
"First generation firewall" incorrect. A packet filtering firewall is a first generation firewall. "Third generation firewall" is incorrect. Stateful Firewall are considered third generation firewalls "Fourth generation firewall" is incorrect. Dynamic packet filtering firewalls are fourth generation firewalls
References:
CBK, p. 464 AIO3, pp. 482 - 484
Neither CBK or AIO3 use the generation terminology for firewall types but you will encounter it frequently as a practicing security professional. See http://www.cisco.com/univercd/cc/td/doc/product/iaabu/centri4/user/scf4ch3.htm for a general discussion of the different generations.

Knowledge-based IDS are more common than behavior-based ID systems.
Source: KRUTZ, Ronald L. & VINES, Russel D., The CISSP Prep Guide: Mastering the Ten Domains of Computer Security, 2001, John Wiley & Sons, Page 63.
Application-Based IDS - "a subset of HIDS that analyze what's going on in an application using the transaction log files of the application." Source: Official ISC2 CISSP CBK Review Seminar Student Manual Version 7.0 p. 87
Host-Based IDS - "an implementation of IDS capabilities at the host level. Its most significant difference from NIDS is intrusion detection analysis, and related processes are limited to the boundaries of the host." Source: Official ISC2 Guide to the CISSP CBK - p. 197
Network-Based IDS - "a network device, or dedicated system attached to the network, that monitors traffic traversing the network segment for which it is integrated." Source: Official ISC2 Guide to the CISSP CBK - p. 196
CISSP for dummies a book that we recommend for a quick overview of the 10 domains has nice and concise coverage of the subject:
Intrusion detection is defined as real-time monitoring and analysis of network activity and data for potential vulnerabilities and attacks in progress. One major limitation of current intrusion detection system (IDS) technologies is the requirement to filter false alarms lest the operator (system or security administrator) be overwhelmed with data. IDSes are classified in many different ways, including active and passive, network-based and host-based, and knowledge-based and behavior-based: Active and passive IDS
An active IDS (now more commonly known as an intrusion prevention system - IPS) is a system that's configured to automatically block suspected attacks in progress without any intervention required by an operator. IPS has the advantage of providing real-time corrective action in response to an attack but has many disadvantages as well. An IPS must be placed in-line along a network boundary; thus, the IPS itself is susceptible to attack. Also, if false alarms and legitimate traffic haven't been properly identified and filtered, authorized users and applications may be improperly denied access. Finally, the IPS itself may be used to effect a Denial of Service (DoS) attack by intentionally flooding the system with alarms that cause it to block connections until no connections or bandwidth are available.
A passive IDS is a system that's configured only to monitor and analyze network traffic activity and alert an operator to potential vulnerabilities and attacks. It isn't capable of performing any protective or corrective functions on its own. The major advantages of passive IDSes are that these systems can be easily and rapidly deployed and are not normally susceptible to attack themselves. Network-based and host-based IDS
A network-based IDS usually consists of a network appliance (or sensor) with a Network Interface Card (NIC) operating in promiscuous mode and a separate management interface. The IDS is placed along a network segment or boundary and monitors all traffic on that segment.
A host-based IDS requires small programs (or agents) to be installed on individual systems to be monitored. The agents monitor the operating system and write data to log files and/or trigger alarms. A host-based IDS can only monitor the individual host systems on which the agents are installed; it doesn't monitor the entire network. Knowledge-based and behavior-based IDS
A knowledge-based (or signature-based) IDS references a database of previous attack profiles and known system vulnerabilities to identify active intrusion attempts. Knowledge-based IDS is currently more common than behavior-based IDS.
Advantages of knowledge-based systems include the following:
It has lower false alarm rates than behavior-based IDS.
Alarms are more standardized and more easily understood than behavior-based IDS.
Disadvantages of knowledge-based systems include these:
Signature database must be continually updated and maintained.
New, unique, or original attacks may not be detected or may be improperly classified.
A behavior-based (or statistical anomaly-based) IDS references a baseline or learned
pattern of normal system activity to identify active intrusion attempts. Deviations from this
baseline or pattern cause an alarm to be triggered.
Advantages of behavior-based systems include that they
Dynamically adapt to new, unique, or original attacks.
Are less dependent on identifying specific operating system vulnerabilities.
Disadvantages of behavior-based systems include
Higher false alarm rates than knowledge-based IDSes.
Usage patterns that may change often and may not be static enough to implement an
effective behavior-based IDS.

Explanation/Reference:
Each Class B network address has a 16-bit network prefix, with the two highest order bits set to 1-0.
The following answers are incorrect:
The first bit of the IP address would be set to zero. Is incorrect because, this would be a Class A network address.
The first two bits of the IP address would be set to one, and the third bit set to zero. Is incorrect because, this would be a Class C network address.
The first three bits of the IP address would be set to one. Is incorrect because, this is a distractor. Class D
& E have the first three bits set to 1. Class D the 4th bit is 0 and for Class E the 4th bit to 1.
Classless Internet Domain Routing (CIDR)
High Order bits are shown in bold below.
For Class A, the addresses are 0.0.0.0 - 127.255.255.255
The lowest Class A address is represented in binary as 00000000.00000000.0000000.00000000 For Class B networks, the addresses are 128.0.0.0 - 191.255.255.255.
The lowest Class B address is represented in binary as 10000000.00000000.00000000.00000000 For Class C, the addresses are 192.0.0.0 - 223.255.255.255
The lowest Class C address is represented in binary as 11000000.00000000.00000000.00000000 For Class D, the addresses are 224.0.0.0 - 239.255.255.255 (Multicast)
The lowest Class D address is represented in binary as 11100000.00000000.00000000.00000000 For Class E, the addresses are 240.0.0.0 - 255.255.255.255 (Reserved for future usage) The lowest Class E address is represented in binary as 11110000.00000000.00000000.00000000 Classful IP Address Format

References:
3Com http://www.3com.com/other/pdfs/infra/corpinfo/en_US/501302.pdf
AIOv3 Telecommunications and Networking Security (page 438)