Final answer:
The absence of a legislative branch would lead to problems like the President gaining too much power, potential unfairness of laws, and a decline in the quality of lawmaking due to lack of diverse input and review, illustrating why checks and balances are vital. The correct option is D.
Step-by-step explanation:
If there was no legislative branch and the President had the power to both make and enforce laws, a few significant problems could arise. The answer to the student's question is (D) All of the above.
Firstly, without a separate legislative branch, the President could become too powerful, combining the duties of creating and executing the law, which could lead to a form of autocracy or dictatorship. This goes against the concept of separation of powers, which is designed to prevent any one branch from gaining too much control.
Secondly, the fairness of laws is often ensured through debate and revision by a diverse group of representatives. If a single person were making all the laws, they may not be fair to everyone, as this would lack the broad representation found in a legislative body.
Lastly, the quality of laws might suffer as the process through which laws are typically written involves extensive review and revision by many individuals, which helps in crafting well-thought-out legislation. The importance of checks and balances is evident in the system established by the Constitution. The correct option is D.