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!
Answer:Unilateral contract
Explanation:
Unilateral contract is a type of agreement or contract in which offer is made and fulfilled through performance .An offeror offers any promise to be fulfilled by him/her if the other party completes the performance act successfully.
According to the question,situation is described as unilateral contract as Sarah is offering $150 to Allison for painting her house in exchange.Allison has to complete house painting to gain promised money even though there is no legal contract between them.
Senatorial elections are not held at the end of every six-year term. They are actually scattered over the six-year term so that not all senators are up for re-election in the same year. There are about one third of the Senators who are up for re-election every two years.
The answer would be letter B.