Those are the methodologies for blockchain technology scalability. They are called layer-1, layer-2, and layer-3 solutions which are to solve the scalability problem for the blockchain technology to improve and be able to accommodate an exponentially growing number of users. As the number of user increase, transactions and lots of other data would also increase that will make the traffic-heavy. A good example of what this layer could solve is the transaction fees that are skyrocketing when the number of users is heavy, thus these layers could reduce the fees to the amount that can be considered reasonable. Each of these layers has its own specifications for the problem they solved. This shows that they will play a very important role for the blockchain technology to prove to be able for the future economy and financial system.
