Which sentence best describes a lifestream? 1) a lifestream shows the activity a user has recently performed on a single website. 2) a lifestream is a time-ordered stream of documents that acts as a user's online diary. 3) a lifestream is a tool to collect a user’s tweets on a single web page. 4) a lifestream allows the user to view who is following their posts on any microblogging site. 5) lifestream shows the number of followers that a user has on a microblogging site.