To compare the vulnerability of the heads of executive departments versus those of regulatory agencies, the correct understanding is as follows:
The heads of executive departments (e.g., Cabinet members) can be fired at the will of the president, meaning they have a higher vulnerability to removal. On the other hand, heads of many regulatory agencies, such as the Federal Trade Commission or the Federal Reserve, often have more protected terms of service and can typically only be removed for cause, such as extreme misconduct.
Thus, the correct statement is:
In the former, heads can be fired at the will of the president; while the heads of the latter can’t be fired during their terms except for extreme misconduct.