Which statement relating to the Income Statement (Profit and Loss account) is correct?

1. In the income statement, movement in Revenue accounts is always equal to movement in Expenses accounts.
2. Income statement account balances are carried forward from one period to the next.
3. Differences in income statement accounts from one period to the next reflect activity in that period.
4. The amount recorded in an account within the income statement reflects the value of transactions in that account during the period.