Avalanche is an Open Source Software (OSS), programmable Smart Contract Platform for Decentralized Applications. AVAX is the native Cryptocurrency of the Platform.
Avalanche uses a quorum based consensus mechanism to achieve agreement in a similar process to a parliament: a proposal (Transaction) is proposed, and voted on to be accepted or rejected. When sufficient votes are cast by the various replicas and accumulated (typically collected through by elected leader replica), then a quorum is achieved, and the agreement is achieved validating the transation. 1)
Source: https://www.avax.network/