Copernicus should be the topic, and the central idea should be how he came up with the heliocentric theory. I hope I helped, please tell me if I am incorrect or if you need more help!
Answer:
Demand and supply
Explanation:
In a market, the demand for a product and the supply of the products affect the price of them.
If a product has limited supply, the price will rise because it is rarer.
If a product has a lot of supply, the price will decrease because it is common.
If product demand is high, prices will rise because sellers want to earn more money.
If product demand is low, prices will sink because sellers need to make some sort of revenue and if the product doesn't sell, they've lost money. If they sell it at a lower price, at least they make some money back.
Of course, there are more factors but demand and supply are the main two, especially in a free market economy.
Answer:
The wind ask the leaves to come over the grassland to play.
