What are the key features of Nigerian political and administrative history, including its highest court, constitutional developments, pre-colonial governance, and civil service characteristics?

Here are the solutions to the questions.

Question 20:
The highest court in Nigeria today is the Supreme Court.

The final answer is $\boxed{\text{C. Supreme Court}}$.

Question 21:
The Richards Constitution (1946) first introduced the concept of regionalism in Nigeria, dividing the country into three regions: Northern, Western, and Eastern.

The final answer is $\boxed{\text{B. Richards Constitution (1946)}}$.

Question 22:
The political system of the pre-colonial Igbo society was largely decentralized, lacking a single central authority. It was characterized by autonomous communities and village councils. This is best described as fragmented and acephalous.

The final answer is $\boxed{\text{C. Fragmented and acephalous}}$.

Question 23:
In the Hausa-Fulani pre-colonial system, the Waziri was the senior official who served as the Prime Minister/Chief Advisor to the Emir.

The final answer is $\boxed{\text{A. Waziri}}$.

Question 24:
A major characteristic of the civil service is "anonymity," which means that civil servants implement government policies without being publicly praised or blamed for them. The political head (minister) takes responsibility.

The final answer is $\boxed{\text{C. They are neither praised nor blamed publicly for government policies}}$.

Question 25:
The 1976 Local Government Reform in Nigeria was significant because it made local government a third tier of government, giving it a distinct constitutional role and financial autonomy.

The final answer is $\boxed{\text{B. Made local government a third tier of government}}$.