What's the difference between .closest() and .parents('selector')?

Question

What\'s the difference between these? Is one more efficient than the other? I\'m a little bit confused to why they both exist. Say I have this markup:

Answer 1

.parent() only goes up one level, while closest() includes the current element, and all parents.

Example (selecting from the bottom div, x = matched elements):

             parent()  parent('body')   .closest('div')  .parents('div')
body     
   div                                                       x
      div       x                                   x
this-->   div                                x