What is a primary purpose of encapsulating packets into frames?

Question

1 provide routes across the internetwork

2 format the data for presentation to the user

3 facilitate the entry and exit of data on media

4 identify the services to which transported data is associated

Answer 1

Hi. Here is a definition. http://www.cknuckles.com/webapps/chap01/extras/encapsulation.html
I would say 1 because the extra information is stripped away.