The User Datagram Protocol (UDP) is used for applications that require a "fire-and-forget" mechanism, where speed is more important than reliability and acknowledgments. UDP doesn't provide acknowledgment or error-checking like TCP.

Browsers connect to web servers using port 443 for HTTPS (Hypertext Transfer Protocol Secure) to ensure secure, encrypted data transfer between the client (browser) and the server. Port 80 is used for standard HTTP.

Protocols ensure interoperability between devices. They define a set of rules and conventions that devices must follow to communicate effectively, ensuring that different devices can understand and work with each other.

In the context of the transport layer, the mechanism that ensures that lost or corrupted data packets are retransmitted is Automatic Repeat reQuest (ARQ). ARQ techniques help in detecting and recovering lost or damaged data packets, thereby ensuring reliable data transmission.

IPv6 is the most suitable IP addressing scheme for a next-gen IoT product where each device requires a unique IP address. IPv6's enormous address space can easily accommodate the potentially vast number of IoT devices, ensuring that each device has a unique address. IPv4 has limited address space and is not practical for large-scale IoT deployments. DHCP (Dynamic Host Configuration Protocol) and MAC (Media Access Control) addresses are not IP addressing schemes but play a different role in networking.

CIDR (Classless Inter-Domain Routing) notation, like /24, represents the subnet mask that divides an IP address into network and host portions. In this example, /24 signifies that the first 24 bits of the address are dedicated to the network, and the remaining bits are for host addressing.

The transport layer differentiates between a temporary network glitch and a more serious issue by monitoring the behavior of the connection. It looks at the number of retransmissions and the time between acknowledgments. If there are a few retransmissions with a brief delay, it's likely a temporary glitch. However, if there are excessive retransmissions or a long delay in acknowledgment, it may indicate a more serious issue that requires a connection reset.

WAN (Wide Area Network) is a network that covers a broad area, connecting multiple LANs that might be on opposite sides of the world. It can span cities, states, or even countries. The internet is the largest example of a WAN.

The correct option is "Switch." Using a switch instead of a hub can help reduce collision domains in an Ethernet network. A switch is an intelligent device that forwards data only to the specific port where the destination device is located, reducing unnecessary traffic and collisions.

The Parity Bit is a basic error detection method that involves adding an extra bit to data to make the number of ones either even or odd. By checking this bit at the receiving end, errors can be detected in the transmitted data.