Hi LauraLodge1, there are a few different kind of streaks depending on the platform and if you ever change time zones things can get a little more complicated. Here is a link to more info about how all of the streaks work and how to keep yours (see Streak Freeze for a safety net) http://duolingo.wikia.com/wiki/Streak

Good luck with your studies! And feel free to check out the other guides on that wiki. They are pretty handy. :)

yes!

Practice every day and get at least "one point" to qualify as a streak. To get "one or more points", just take a 30 second Timed Practice test.