Who's unique features? I'm not answering for points.. I'd like to help but.. ✨
Answer:
unrest
Explanation:
overworking and sleepless night contribute to a stress
Answer:
An e-mail can be sent to multiple people at the same time.
An e-mail uses a simpler format than the business letter.
An e-mail must be addressed to a specific person or department.
An e-mail is more modern; nobody uses snail mail anymore