What chain is Aptos on?

Could you please elaborate on the blockchain technology utilized by Aptos? I'm curious to know which specific chain it operates on. Could you provide some insights into the technological foundation of Aptos and how it differs from other blockchain platforms? Additionally, is there any unique feature or advantage that Aptos offers on its chosen chain? I'm interested in understanding the reasons behind its selection and how it contributes to the overall functionality and performance of Aptos. Thank you for your assistance in clarifying this matter.