Which Amendment made in the constitution, on April 1974, defines the boundaries of Pakistan?

Which Amendment made in the constitution, on April 1974, defines the boundaries of Pakistan?

اپریل 1974 کو آئین میں کی گئی کون سی ترمیم پاکستان کی حدود کا تعین کرتی ہے؟
Explanation

The First Amendment to the Constitution of Pakistan, enacted on May 4, 1974, redefined Pakistan's boundaries and eliminated references to East Pakistan.

The amendment also redefined Pakistan's federal and naval treaties.

The First Amendment was introduced during the tenure of Zulfikar Ali Bhutto to protect against internal and external destabilization.