People living in which area are MOST LIKELY to suffer the effects of desertification in Sub-Saharan Africa?

Practically every country of Africa is prone to desertification, but the Sahelian countries at the southern fringe of the Sahara are particularly vulnerable. Only about 19% of Niger is non-desert and of this 17% belongs to high and very high vulnerability classes.

giant impact theory - the moon was formed from the collision between earth and another mars-sized body.

colliding planetesimals hypothesis - the moon was formed from the same cloud of material as earth.

capture hypothesis - the moon was locked into orbit by earths gravity as it was passing by it.

accretion hypothesis - the moon was formed from collisions and combining of planetesimals.

i think this is right, if not and you know better let me know.