i'm not really sure but i don't think the fall of nubia/kush had anything to do with being taken over by the kindom of aksum.. i may be incorrect tho!
Explanation:
Development occurs in many types depends upon how u want it to develop and how you helping in it to develop it more easily. As per the psychologists (Developmental psychologists), the development of an individual or child occurs in a orderly or sequential way and in different areas simultaneously.
Answer:
the loss of potential gain from other alternatives when one alternative is chosen.
Explanation:
I don't know but I will try my best on it.