In your own words, explain efficacy.

i suggest it is anadiplosis

the development of trade during the middle age increased to the change given in the agriculture, which gave money, industry and markets a bigger importance in economy. the agriculture production was more than the consumption, which meant the creation of wider markets out of the areas. besides, with the end of multiple wars, the population increased and new trade routes were created.

an great real life example for the lottery principle is the real life lottery itself. it adheres to the lottery principle so much it's even called lottery. you apply for the lottery in the manner of getting a ticket and if you are lucky, the goods are distributed to you, in this case, the huge amounts of money. there are other real life example but this is the best one.