What chain is Coinbase using?

I'm curious to know, could you please clarify which blockchain network is Coinbase currently utilizing for its transactions and operations? As a leading cryptocurrency exchange, the choice of blockchain technology they employ is of great significance to both traders and investors alike. Understanding the specifics of their platform's underlying infrastructure can provide valuable insights into its security, scalability, and potential for future growth. So, which blockchain chain does Coinbase leverage to support its diverse range of services?