The functions of Windows operating system which allows you to do are:
(i) Access applications (programs) on computer (word processing, games, spread sheets, calculators and so on).
(ii) Load any new programs on to the computer.
(iii) Manage hardware such as printers, scanners, mouse, digital cameras etc.
(iv) Manage how files are stored on your computer.
(v) Change computer settings such as colour schemes, screen savers and the resolution of monitor.

It is a folder which contains all deleted files and folders have an opportunity to recover from it.

Difference between Thunderbird and Firefox in Ubuntu:
(i) Thunderbird is inbuilt email software of ubuntu whereas Firefox is a web browser.
(ii) Thunderbird is used to access email such as Gmail, hotmail whereas Firefox is used to open web pages including e-mail.

(i) Ubuntu has less hardware support for commercial/industrial/medical/ logistical therefore its less voted for use in big time backends.
(ii) Ubuntu doesn't support middlewares such as C panel, cloud linux and a plethora of other infrastructure or monitoring tools.
(iii) Hard to install graphic drivers especially for old hardwares. It is not possible to play the modern games, because of poor graphics quality.
(iv) The user switching from windows will not like the user experience on Ubuntu and will have difficulty in operating the OS.
(v) Ubuntu is not capable of playing MP3 files by default.