Without religion humanity wouldn't be aware of its spiritual nature, eternal destiny, and/or moral guidance from the beginning of time.
Religion is a creation of mankind, therefore it would cease to exist if man were no longer here. If animals got smart enough then sure.
Which religion? There are hundreds practiced today, thousands throughout mankind's history.
It depends on the religion.
As all people of mankind was created.
The person who wrote that evidently thought that religion is harmful for humans - that it enslaves them.
It is the native religion of Japan and was once its state religion.
Judaism did not begin within another religion.
India
About 550BCE
Islam
Polytheists.
Cults have existed for centuries, with notable examples dating back to ancient civilizations. The modern concept of cults began to emerge in the late 19th and early 20th centuries, becoming more prevalent in the 1960s and 1970s with the rise of new religious movements and charismatic leaders.