Answer:
Reversibility
Explanation:
In simple words, Because it represents the commencement of reasoned or practical reasoning, Piaget believed the tangible stage to be a crucial turning point in a preschooler 's cognitive growth. The kid has reached the age where logical reasoning or procedures (i.e. principles) may be applied, but only to tangible things (thus concrete operational).
Answer:
Trans-Sahara trade is one of the oldest trading networks in Africa.
Explanation:
The trading network requires to travel across the Sahara between sub-Saharan Africa and North Africa. Existing since prehistoric times, it reached its peak in the 8th century. In West Africa, the changes came in Ghana when the Almoravids sacked the city and the Ghāna Empire decline.
Mali rise in the 13th century as gold became the core of the trans-Saharan trade. The Trans-Sahara trade saw the rise of empires like Mali, Songhay, and Bono-Mansu. Expansion of urban centres and towns happened as Kano became one of the urban centres in West Africa. Trade also saw the rise of trading classes call the Wangara.
