Answer:
The sentence seems to be complete except if it is complete it needs a period to be actually completed
<span>For the first time in decades, Baby Boomers have been outnumbered by another group—the Millennials.</span>
Hiram Bingham discovered Machu Picchu on July 24th 1911
#1. Comma is used to off set the sentence
Explanation:
A formal email is an email used while conducting business with a new associate or executive, sending a professional inquiry, or corresponding about a job.