Which of the following pairs is mismatched

1] crown-enamel

2] root-root canal

3] alveoli-periodontal ligament

4] pulp cavity-cementum

5] apical foramen-blood supply

Actually, the dental alveoli refer specifically to the "tooth socket" and so are most definitely associated with the periodontal ligaments, although I'm unsure which of the above is mis-matched. If I remember correctly, the pulp cavity has some other layer between it and the cementum, but that may not be correct.

ALVEOLI ARE IN THE LUNGS AND HAVE NOTHING TO DO WITH THE PERIODONTAL LIGAMENT WHICH SURROUNDS TEETH.

THE PULP CAVITY IS A COMPLETELY A SEPARATE PART OF THE TOOTH AND IS NOT PART OF THE CEMENTUM WHICH CONNECTS THE ROOT SURFACE TO THE PERIODONTAL LIGAMENT.

THE OTHERS HAVE A DIRECT CORRELATION.