Classify Each of the Following Controls as Preventive,detective,or Corrective

Essay

Classify each of the following controls as preventive,detective,or corrective.
Periodic bank reconciliation
Separation of cash and accounting records
Maintaining backup copies of master and transaction files
Pre-numbering of sales invoices
Chart of accounts
Retina scan before entering a sensitive R & D facility
Resubmission of error transactions for subsequent processing
Internal auditor rechecking the debits and credits on the payment voucher
Depositing all cash receipts intact
Hiring qualified accounting personnel