Which two of the following best identify the central ideas of the lost generation

we have no idea what story or poem you mean? ?

explanation:

where are the options? i can try to if you add them : )

  this riddles' answer is library.

  the "leaves" are a reference to the books' pages that the library contains; the branches are a network of libraries that connect multiple libraries' collections, resources, and items in a system of a common database, integrating them; the branches' organization are a useful management tool for coordinating the multiple collections many libraries have.