Workers' wages are a cost of doing business. This is called an Expense and would probably be classified as Wage Expense. Another Question Go to Table of Contents 1c. It would probably be classified as an Asset called Office Equipment. Another Question Go to Table of Contents 1d.
Profit is the excess of Revenues over Expenses.
It is nothing more than a calculation. Another Question Go to Table of Contents 2a. Assets would not decrease. The business didn't give anything up, it actually got something. Liabilities would not decrease, the business didn't pay a bill.