Okay kiddo, imagine that you and your friends are playing a game where you are all selling lemonade. In the beginning, you have to make everything from scratch - squeeze the lemons, mix the sugar, and make the lemonade. This takes a lot of time and effort, but you start selling your lemonade to your neighbors and make a bit of money.
As you get better at making lemonade, you start to make more and more each day. You even get your parents to help you out, and you start using fancier equipment to make the lemonade. Your lemonade stand becomes really popular, and you start selling to people outside of your neighborhood.
One day, a big company comes along and offers to buy your lemonade stand for a lot of money. They have the resources to make even more lemonade and sell it all over the world. You agree to sell the stand, and before you know it, their lemonade is being sold in supermarkets all over the country.
This is kind of like what happens in developed markets. In the beginning, a country might not have a lot of resources or technology to produce goods and services efficiently. But over time, they start to develop their economy and become more advanced. They start using better equipment, improve their processes and become more efficient.
As they become more developed, they can produce even more goods and services, and they start selling to other countries. Companies from other countries start investing in them, and they become a big player in the global economy.
Think of it like your lemonade stand growing up and becoming a big company that sells lemonade all over the world. That's kind of what happens in developed markets!