can you please check my answer for questions 2,3,4,5? I am not sure about them. Please also give me the explaination for each of them.

2. During the Sales Order Activity of the Revenue Process, name 2 verifications that must be done before the sales order can be completed: - Customer's purchase order and Inventory Master File 3. During the Shipping Activity of the Revenue Process, which document would be used first during a transaction - Picking List or Packing Slip? Picking List 4. During the Billing Activity of the Revenue Process, one Open File and one Master File are updated after the invoice is created. What files are updated? Open File - _ Customer Invoice File Master File - Customer Master File 5. During the Cash Collection Activity of the Revenue Process, it is important to separate 2 items. What 2 items are separated upon a company's receipt of a payment from a customer? - Remittance Advice and customer Check (Payment)