Identify the structural characteristic that classifies the Indian judicial architecture as an 'integrated' system:
1. Regional High Courts possess exclusive jurisdiction to adjudicate and enforce only the legislative acts passed by their respective State assemblies.
2. The enforcement of statutes derived exclusively from the Concurrent list is legally restricted to the Supreme Court.
3. The Supreme Court assumed the role previously held by the British Privy Council as the final venue for legal appeals.
4. The entire network forms a single hierarchy wherein legal precedents established by apex courts are absolutely binding on all subordinate tribunals.