Cities of high population densities develop on plains because I. act as climate barriers II. have fertile…

Analyze the question: We are asked why cities with high population densities tend to develop on plains. We must judge each statement (I to IV).

Concept: Plains are large, flat, low-lying areas. People settle densely where there is food (agriculture), easy construction, and easy movement of goods and people.

Evaluate each statement:

• I. Act as climate barriers: This is false. Mountains and highlands act as climate barriers (they cause relief rainfall and block winds). Plains are open and do not block climate systems.
• II. Have fertile soils: This is true. Plains, especially river floodplains and alluvial plains such as the Niger-Benue valley, have deep, fertile alluvial soils that support farming and large populations.
• III. Lack heavy rainfall: This is false as a reason. Lack of heavy rainfall is not what attracts dense settlement, and plains can receive plenty of rain. It is not a defining advantage.
• IV. Have terrain with ease of communication: This is true. Flat land makes it cheap and easy to build roads, railways, and airports, and to build houses and industries. This encourages trade and urban growth.

Correct statements: II and IV only.

Answer: Option D.

Tip: For "why do people settle densely on plains" questions, remember the key words flat, fertile, and easy transport. Be careful with options about "climate barriers": that phrase is linked to mountains, not plains.