Why did coastal city-states develop in East Africa?

Whether or not a given study has the possibility of causing harm to participants:

Pj conducts an experimental study on the effects of soft music during high stakes science testing. he randomly assigns students at the school. in one condition he does not provide music for testing while in the other group he does provide the music. he administers a pretest at the beginning of the year and a posttest at the end of the year. pj’s design is best described as a: a.static group comparisonb. pretest-posttest control group designc.control-group-time-series designd. nonrandomized control-group pretest-posttest design

New zoya is a country of english-speaking people and has a very profitable economy. which of the following countries is most likely to be the closest to new zoya in terms of cultural distance? sulfura, which has a very profitable economy and where people speak sulfuran valyria, where people speak english and have a low standard of living danver, which has the same wealth and per capita income as new zoya novalandia, which is located close to new zoya and is easily accessible by road