In SAP-C02, Route 53 isn't just a "DNS service." It's the brain of global traffic routing, the link in hybrid DNS, and a security layer via DNSSEC. If Day 2 covered keyword mapping for 7 routing policies, today dissects the algorithms actually running inside—Health Check decision logic, Geoproximity Bias mathematics, Resolver endpoint internal operation. Without algorithm-level understanding when "why this policy" is questioned, you waver between similar options.
Route 53 Health Check appears simple: poll endpoint, good response = Healthy, bad = Unhealthy. SAP exams question the internal algorithm.