Erg Chebbi Erg Chebbi Erg Chebbi () is one of Morocco's several ergs – large seas of dunes formed by wind-blown sand. There are several other ergs such as Erg Chigaga near M'hamid. Technically all these ergs are within an area of semi-arid Pre-Saharan Steppes and not part of the Sahara desert which lies some distance to the south. In places, the dunes of Erg Chebbi rise up to 150 meters from the surrounding hamada (rocky desert) and altogether it spans an area of 28 kilometers from north to south and up to 5–7 kilometers from east to west lining the Algerian
ERG theory ERG theory ERG theory is a theory in psychology proposed by Clayton Alderfer. Alderfer further developed Maslow's hierarchy of needs by categorizing the hierarchy into his ERG theory (Existence, Relatedness and Growth). The existence group is concerned with providing the basic material existence requirements of humans. They include the items that Maslow considered to be physiological and safety needs. The second group of needs is those of relatedness – the desire people have for maintaining important interpersonal relationships. These social and status desires require interaction with others if they are to be satisfied, and they align with Maslow's social need