Which one of the following lakes of West Africa has become dry and turned into a desert ?

Lists Mali among countries where desertification is particularly extensive and severe, and highlights Sahel droughts that drive land degradation.

A student could note that Lake Faguibine lies in Mali's Sahel zone and therefore is in a region prone to drying and convert that into a hypothesis to check with maps or local lake reports.

Explains that in regions of unreliable rainfall, lakes can dry completely during dry seasons and that lakes in hot dry regions disappear by evaporation/percolation.

Combine this general rule with rainfall trends for the Faguibine basin to assess whether reduced inflow could have dried the lake.

Identifies the Sahel (including Mali) as a worst-affected area for soil erosion and related land degradation, which can accompany loss of surface water bodies.

Use the linkage between Sahel land degradation and hydrological change to infer that lakes in the region are vulnerable, then check local hydrology for Faguibine.

Gives UNCCD definition: prolonged droughts cause desertification and spread of deserts in adjacent areas, linking climatic variation to loss of productive land.

A student could apply this definition to assess whether extended droughts in Mali could have turned a lakebed into desert-like terrain and seek drought records for the area.

Notes West African trade winds become dry and dust-laden by the time they reach continental interiors, reducing moisture inland.

Combine this atmospheric pattern with the lake's inland location to argue the region has climatological tendencies that support drying; then verify with local climate data for Faguibine.