Please answer these questions in detail and thorough explanation:

1. What is allowance for doubtful account. what is it classified as?

2. What is the impact of write-off of an uncollectible account?

3. What is bad debt expense, how and when is it recorded?

4. What does a debit balance in the Allowance account mean?

5. What are some items that go into determining Cost of inventory?

6. What are some entries to record bad debts?

7. What is the concept of lower of cost or market?