Hello friend greetings to you, hope you are doing well and good there.

You have done a nice attempt to answer these questions here. The graph shows us a vavid description of the Blockchain layers. You have beautifully explained the layer 3 block chain that specializing fractal scalability use horizontal sharding. You are right in saying that it improve the transactions rate of the blockchain.

The concept of Sidechains and Roll-up are too much easy. You have a nice understanding of it too. Overall your post is amazing, it's great to see your good effort here.

I wish you very best of luck in this contest.