Final answer:
To keep a worksheet protected in Excel, you should create a password which prevents unauthorized users from changing the worksheet's protected status.
Step-by-step explanation:
To ensure that others cannot change the worksheet from protected to unprotected, you should create a(n) password. When you protect a worksheet, Excel will prompt you to enter a password. This password acts as a key, allowing only those with the password to change the protection status of the document. It is crucial to choose a strong password that combines letters, numbers, and symbols to prevent unauthorized access. Remember that if you forget the password, it may be difficult or impossible to unprotect the worksheet, so keep it in a safe place.