context: Yemen's land area is about 528,000 km². The capital is or and can be divided geographically into four regions. It is a region of the Red Sea coast, the western mountains, the eastern mountains, and the northern Ruhl Al-Hali Desert. The Red Sea coast, called Tihama, is very dry, and rivers flowing in the mountains are hard to see, and exist in the form of wadi or groundwater. The western mountainous regions have a lot of precipitation, so they do terraced farming. Sorghum is the main product, and fruits such as cotton and mango are also grown. The area has large temperature differences between day and night. The eastern part is 2,000m above sea level, and the temperature difference is larger than the western part. It may show a temperature difference of 30 ℃ during the day and 0 ℃ during the night. In the eastern region, barley or wheat is grown. There are Bedouin nomads in the Rual-Al-Hali Desert, but they do only camel nomads. On the coastal plains of the Gulf of Aden, crops are harvested using repairs. The temperature is high on the coast of the Red Sea and the central highlands are comfortable. In the central part, annual rainfall of 400 to 1,000 mm is observed. The Red Sea coastal plain has a high temperature and high humidity of 40 ~ 50 ℃.
question: What is the capital of Yemen?
answers.text: or