4.How did the East African coastal trading cities lose power?

Mostly because the influence of European Empires.

in the past, the Africans handled their trading cities independently. This help their region generate wealth from trading with other countries.

When the Europeans Colonists (such as the Portuguese and the dutch)  saw the potential that the trading cities possess, they start to made various effort to take control of them. Starting from influencing African politics , or even some direct attacks. Eventually, East African coastal trading cities started to be taken over and lose its power.

giant impact theory - the moon was formed from the collision between earth and another mars-sized body.

colliding planetesimals hypothesis - the moon was formed from the same cloud of material as earth.

capture hypothesis - the moon was locked into orbit by earths gravity as it was passing by it.

accretion hypothesis - the moon was formed from collisions and combining of planetesimals.

i think this is right, if not and you know better let me know.