High availability in cloud computing is often achieved by distributing resources across multiple Availability Zones within a region. Each Availability Zone operates independently with its own power, cooling, and networking, which means that if one zone experiences a failure, the other zones can continue to operate without being affected, hence providing redundancy and continuous operations. Single Availability Zones can potentially affect high availability due to localized disasters or failures, one region deployment doesn't provide isolation from regional issues, and a single edge location is designed more for content delivery optimizations rather than availability.