Evaluate graduate-level understanding of distributed-systems consistency models: formal semantics of linearizability, sequential and causal consistency, and eventual consistency; the guarantees they provide and client-visible anomalies; implementation approaches (replication, leader vs leaderless, anti-entropy); and design trade-offs affecting availability, latency, scalability, and partition tolerance. Tasks include formal definitions, execution analysis for model compliance, and justification of model selection for given workloads.