The following unrelated events occurred after the balance sheet date but before the audit report was prepared:

The granting of a retroactive pay increase

Determination by the federal government of additional income tax due for a prior year

Filing of an antitrust suit by the federal government

Declaration of a stock dividend

Sale of a fixed asset at a substantial profit

How each of the above items might have come to the auditors attention? Why is it the auditors responsibility to recognize each of these in connection with the audit report and opinion?