I ve been playin kapilands for 2 weeks i need some help from experienced players

1) What is the use of research? I recently reached 5 quality in gas. I would like to know how it affects to npc customers. I mean the higher quality product has, the higher price the product will have k ? If this is the case, is there a formula between the customer demand and quality level ?
2) What is optimize? How it affects the stuff?
3) Advertises lowers the time the product sold in the stores am i right? Is there a formula for it? How many advertisements is good enough for a product, lets say for 1k gas?
4) How can i increase the content rate of the customers? Higher content level helps to inrease the price of the product or time? Again is there a formula for it?
5) I dont understand supply and demand stats totally. For example in France animal foods demand 46.153.828 and supply is 1. If I produce and sell animal food in france, will there be a change in supply? And how this affects the price of the good and time the good is being sold?
I guess thats it for now. I m really curious about my questions hope they ll get answered
