What is the fiscal year? Why might companies choose to use a fiscal year that is not a calendar year?

Is it necessary to do a physical count of inventory if the company is using a perpetual system?  Why or why not?  What sort of company would likely use a perpetual system?  What sort of company would likely use a periodic system?  (Provide specific examples).

iv Why there is a difference among the company tax rate times with the firm’s accounting income?  highlighting the reasons for differences.

Based on a change in economic conditions, Company X has determined that its allowance for doubtful accounts needs to increase. What type of accounting change is this? accounting policy accounting error accounting estimate