What internal control procedure that would reduce the following risks in a manual system: Explain

1. The purchasing department may not be notified when goods need to be purchased.
2. Accounts payable may not be updated for items received.
3. Purchase orders may be prepared on the basis of unauthorized requisitions.
4. Receiving clerks may steal purchased goods.
5. Payments may be made for items not received.
6. Amounts paid may be applied to the wrong vendor account.
7. Payments may be made for items previously returned.
8. Receiving clerks may accept delivery of goods in excess of quantities ordered.
9. Duplicate payments may be issued for a single purchase transaction.