"The Data Link layer also determines how data is placed on the wire by using an access method. The wired access method, carrier-sense multiple access with collision detection (CSMA/CD), was once used by all wired Ethernet networks, but is automatically disabled on switched full-duplex links, which have been the norm for decades. Carrier-sense multiple access with collision avoidance (CSMA/CA) is used by wireless networks, in a similar fashion."

Network traffic is the amount of data moving across a computer network at any given time. Network traffic is broken down into data packets and sent over a network before being reassembled by the receiving device or computer1.
Network traffic has two directional flows, north-south and east-west. North-south traffic refers to client-to-server traffic that moves between the data center and the rest of the network (i.e., a location outside of the data center). East-west traffic refers to traffic within a data center, also known as server-to-server traffic12.
A data center is a facility that houses computing and networking equipment, such as servers, switches, routers, firewalls, and storage devices. Data centers provide centralized processing, storage, and access to data and applications for organizations and users3.
Data centers need to handle both north-south and east-west traffic efficiently and securely. North-south traffic is typically generated by users or customers who access data or applications hosted in the data center from the internet or other networks. East-west traffic is typically generated by applications or services that communicate with each other within the data center.
The question asks which of the following describes traffic going in and out of a data center from the internet. The correct answer is B. North-South, because this is the type of traffic that flows between the data center and the external network. The other options are incorrect for the following reasons:
A . Demarcation point is the physical point where the responsibility for the network changes from one party to another, such as from a service provider to a customer. It does not describe network traffic.
C . Fibre Channel is a high-speed network technology that connects servers and storage devices in a data center. It does not describe network traffic, but rather a network protocol.
D . Spine and leaf is a network topology that consists of two layers of switches: spine switches that interconnect with leaf switches, and leaf switches that connect to servers and devices. It does not describe network traffic, but rather a network design. Reference:
1: What Is Network Traffic? Definition and How To Monitor It
2: 32 Flashcards | Quizlet
3: Data center - Wikipedia
4: Data Center Traffic Patterns: North-South vs. East-West
5: Demarcation point - Wikipedia
6: Fibre Channel - Wikipedia
7: Spine and leaf - Wikipedia

When a user is unable to perform a reverse DNS lookup of an IP address to a hostname, the missing DNS record type is the PTR (Pointer) record. Here's what you need to know:
PTR (Pointer) Record:
The PTR record maps an IP address to a hostname (reverse DNS lookup).
It is used to resolve IP addresses back to domain names.
For example, if you have an IP address (e.g., 192.168.1.10), the PTR record would provide the corresponding hostname (e.g., server.example.com).

Before making any recommendations, a network technician should first capture a network baseline, which is a snapshot of the current performance of the network. This will give the technician a baseline to compare against after any changes are made. According to the CompTIA Network+ Study Manual, the technician should "capture the state of the network before making any changes and then compare the performance after the changes have been made. This will provide an accurate baseline to compare the performance of the network before and after the changes have been made."

802.11 ax is the latest wireless standard that operates in both the 2.4GHz and the 5GHz bands. It offers higher throughput, lower latency, and improved efficiency compared to previous standards. It also uses technologies such as OFDMA and MU-MIMO to reduce interference and increase capacity in dense environments. Therefore, 802.11 ax is the best choice for a wireless network in an office building with high saturation on both bands.
Reference
Part 3 of current page talks about the benefits of 802.11 ax and how it improves network performance in congested areas1.
CompTIA Network+ N10-008 Exam Cram covers the wireless standards and their characteristics in Chapter 5. It also provides practice questions and explanations for the exam.