An altcoin is also known as a Bitcoin Alternative or Alternative Cryptocoin, which refers to all cryptocurrencies other than Bitcoin. Most of the cryptocurrencies in the early stage were created through forking (copying Bitcoin codes).
A stablecoin is a cryptocurrency with a stable price, which is often pegged to a legal tender in the real world. Take USDT, currently the most commonly used stablecoin, for example, USDT is pegged to the US dollar, with 1 USDT = 1 USD.
Derivatives are born due to demand. It is speculation or risk aversion. Choosing the appropriate crypto derivatives allows you to get twice the result with half the effort.
As a blockchain project, Solana aims to optimize network scalability and increase speed, and adopts a unique proof of history algorithm to significantly improve the efficiency of on-chain transactions and sequencing.