Common mistakes that writers make include ones relating to

life is life. how is ur life too?

i'm pretty sure i had this question the other day and b was the right answer.

services provided to people and organizations.answer

  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.