The app file type is designed to run under macOS as an application file bundle. macOS uses application bundles to store executable files and related resources, such as libraries, image files, and localized content, in a single directory hierarchy. This approach simplifies application management and execution within the macOS environment.

WPA2 is the only protocol among the options that supports fast roaming between networks. Fast roaming, also known as IEEE 802.11r or Fast BSS Transition (FT), enables a client device to roam quickly in environments implementing WPA2 Enterprise security, by ensuring that the client device does not need to re-authenticate to the RADIUS server every time it roams from one access point to another1. WEP, WPA, LEAP, and PEAP do not support fast roaming and require the client device to perform the full authentication process every time it roams, which can cause delays and interruptions in the network service.
References:
The Official CompTIA A+ Core 2 Study Guide2, page 263.
WiFi Fast Roaming, Simplified3

Developer Mode on Windows 10 is a feature that allows developers to test and debug their applications on their devices, as well as sideload apps and access other developer tools12. To enable Developer Mode, the user needs to go to the Settings app, select Update & Security, choose For Developers, and switch to Developer Mode123. However, enabling Developer Mode requires internet connectivity, as Windows will download and install a package of features, such as Windows Device Portal and SSH services, that are necessary for Developer Mode124. If the user does not have internet connectivity, they will receive a "failed to install package" message when trying to enable Developer Mode4. Therefore, the first thing that the technician should do is to ensure that the laptop has internet access, either through Wi-Fi or Ethernet, and then try to enable Developer Mode again4

https://www.makeuseof.com/tag/difference-32-bit-64-bit-windows/
After upgrading from a 32-bit Windows OS to a 64-bit OS, the company will be able to fully take advantage of the RAM of the computer. This is because a 64-bit operating system is able to use larger amounts of RAM compared to a 32-bit operating system, which may benefit the system's overall performance if it has more than 4GB of RAM installed

In this case, abnormal behavior after opening a suspicious email suggests malware might have infected the device. A full factory reset is recommended to remove any persistent malware, especially when a restart does not resolve the issue. Deleting the email or reinstalling the browser will not remove the malware already on the device.
Reference: Core 2, Domain 2.3 - Malware detection and removal.