Ubuntu is a Linux distribution that is commercially backed by Canonical. Canonical provides support and services for Ubuntu, making it a popular choice for both desktop and server environments.

The most suitable Bash construct for taking different actions based on the day of the week is the case statement. You can use case to evaluate the value of the day and define different actions for each day. Options 1, 3, and 4 are not specifically designed for this purpose; they serve different scripting needs.

The chage command in Linux allows you to change the expiration date of a user's password. It provides a range of options to manage password-related settings, including password expiration.

When a script is not behaving as expected, you can add the set -x option at the top of the script to display each command before it's executed. This is a valuable debugging technique that helps you identify issues in your script by showing each command as it is processed.

A common method to secure SSH beyond just password authentication is to enforce key-based authentication. This method increases security by requiring users to possess a private key in addition to their password, making it much more difficult for unauthorized users to access the system.

You would likely use the getopt command to parse command-line options with both short and long formats. getopt is a versatile command for handling command-line arguments and options in shell scripts, allowing you to specify both short and long options.

QEMU, when paired with KVM (Kernel-based Virtual Machine), leverages "hardware" virtualization for better performance. Hardware virtualization allows the virtual machine to directly access the physical hardware, resulting in improved performance compared to software emulation.

In shell scripting, a loop that processes each item in a list one by one is known as a for loop. The "for" loop allows you to iterate through a list of items, such as files or elements in an array, and perform actions on each item. It's a fundamental construct for automation and scripting tasks.

The tc command is used to monitor and manipulate IP traffic control settings in Linux. It allows you to manage Quality of Service (QoS), bandwidth, and traffic shaping on network interfaces, making it a crucial tool for network administrators.

Services in Linux that start at boot and run in the background are commonly referred to as daemons. Daemons are long-running background processes that perform various tasks such as serving network requests, managing hardware devices, and more.