Context: To the south, the Sahara is bounded by the Sahel, a belt of dry tropical savanna with a summer rainy season that extends across Africa from east to west. The southern limit of the Sahara is indicated botanically by the southern limit of Cornulaca monacantha (a drought-tolerant member of the Chenopodiaceae), or northern limit of Cenchrus biflorus, a grass typical of the Sahel. According to climatic criteria, the southern limit of the Sahara corresponds to the 150 mm (5.9 in) isohyet of annual precipitation (this is a long-term average, since precipitation varies annually).

Question: What is to the south of the Sahara?
Answer: Sahel

Question: What kind of climate does the Sahel have?
Answer: dry tropical

Question: What is the long term precipitation average of the Sahara?
Answer: 150 mm

Question: What type of Savanah is north and south of the Sahara
Answer: Unanswerable

Question: What drought tolerant plant grows south of the Sahara?
Answer: Unanswerable

Question: What type of grass grows on the northern Shara?
Answer: Unanswerable

Question: How much rain does the Sahara get?
Answer: Unanswerable

Question: What is to the north of the Sahara?
Answer: Unanswerable

Question: What is the Cenchrus biflorus a member of?
Answer: Unanswerable

Question: What is the short term southern limit of the Sahara's precipitation?
Answer: Unanswerable

Question: What extends across Africa from north to south?
Answer: Unanswerable

Question: What type of grass is atypical to the Sahel?
Answer: Unanswerable