"there is" and "there are"

Is there university in Loma Bonita?
  -yes, there is
Are there tree in Loma Bonita?
 -yes, there are
Are there schools in Loma Bonita?
 -yes, there are
Are there donkis in Loma Bonita?
 -yes, there are
Is there Wallmart in Loma Bonita?
 -no, there isn't