Many villages in the sahel have been settled ?

Assuming that you're referring to the villages in the Sahel during the era of Sahelian Kingdoms, a lot of them settled on the edge of Sahara, on its southern border to be precise. The southern border of Sahara is filled with forests and have enough resource to sustain their living. But they cant go any further because they were hindred by the Ashanthis and Yoruba

Answer herbicide-resistant soybeans;

Mexico has a host of environmental problems, including significant chemicalpollution  from factory discharges and waste dumping, but the main threat to itsbiodiversity  probably stems from  deforestation  and other natural habitat losses. forest habitat is lost for a number of reasons