Final answer:
The concept of replacing traditional hardware and software needed to create and test applications with cloud-based resources is referred to as Platform as a Service, or PaaS.
Step-by-step explanation:
The cloud computing concept that is best described as focusing on replacing the hardware and software required when creating and testing new applications and programs from a customer's environment with cloud-based resources is Platform as a Service (PaaS). PaaS provides a platform allowing customers to develop, run, and manage applications without the complexity of building and maintaining the infrastructure typically associated with developing and launching an app. By using PaaS, developers can easily access a complete software development environment, including development tools, infrastructure, and operating systems, all from a cloud provider.