Which of the following services helps in scaling resources in cloud computing?

Amazon EC2, or Elastic Compute Cloud, is primarily designed to provide scalable computing capacity in the cloud. It allows users to launch virtual servers, known as instances, which can be easily scaled up or down based on demand. This means that if application traffic increases, users can add more EC2 instances to handle the load; conversely, they can reduce the number of instances during periods of low demand to save on costs.

The elasticity of Amazon EC2 is a fundamental feature of cloud computing, offering significant flexibility to adjust resources as required in real-time. Users can also take advantage of features like auto-scaling, which automatically adjusts the number of running instances based on incoming traffic, ensuring optimal performance and cost-efficiency.

While other services like Amazon RDS (for relational database services) can also scale, they do so within their specific operational domain. Amazon CloudFront is primarily a content delivery network (CDN), enhancing the delivery speed of websites and applications rather than scaling underlying compute resources. Amazon Route 53 is a scalable DNS web service that helps manage incoming traffic to application endpoints, but it does not directly scale resources in the cloud itself. Thus, Amazon EC2 stands out as the service explicitly dedicated to scaling computing resources.