Final answer:
The initial investment of $10,000 in the sea shell business is recorded as an increase in assets in the accounting equation.
Step-by-step explanation:
In accounting, when Sally Smith starts her sea shell business with an initial investment of $10,000 in cash, it is recorded as a transaction in the accounting equation. The accounting equation is Assets = Liabilities + Equity. Since Sally's investment is in cash, it increases the Assets side of the equation. Therefore, the transaction is recorded as: