Federal government on Thursday submitted to the Supreme Court its statement in reply to the set of petitions challenging different provisions of the 18th Constitutional Amendment, especially the mechanism of appointing superior courts' judges, report said. The government in its reply says Parliament is sovereign institute having authority to amend the constitution. The SC on Monday directed the lawyers for the federation to file a concise statement in response to some 15 identical petitions. The 17-member larger SC bench, headed by Chief Justice of Pakistan Iftikhar Muhammad Chaudhry, also sought transcripts of nine-month deliberations of the parliamentary committee which hammered out the 18th Constitutional Amendment and the subsequent debate in the National Assembly which adopted it unanimously.