Cloud environments depend heavily on API calls for management and automation. Any vulnerability with the APIs can cause significant risk and exposure to all tenants of the cloud environment. Resource pooling and elasticity could both be impacted by insecure APIs, as both require automation and orchestration to operate properly, but automation is the better answer here. Redundancy would not be directly impacted by insecure APIs.

A UPS can provide line conditioning, adjusting power so that it is optimized for the devices it serves and smoothing any power fluctuations; it does not offer any of the other listed functions.

According to "The NIST Definition of Cloud Computing," in IaaS, "the capability provided to the consumer is to provision processing, storage, networks, and other fundamental computing resources where the consumer is able to deploy and run arbitrary software, which can include operating systems and applications. The consumer does not manage or control the underlying cloud infrastructure but has control over operating systems, storage, and deployed applications; and possibly limited control of select networking components (e.g., host firewalls).

Explanation
The following groups form the key roles and functions associated with cloud computing. They do not constitute an exhaustive list but highlight the main roles and functions within cloud computing:
- Cloud customer: An individual or entity that utilizes or subscribes to cloud based services or resources.
- CSP: A company that provides cloud-based platform, infrastructure, application, or storage services to other organizations or individuals, usually for a fee; otherwise known to clients "as a service.
- Cloud backup service provider: A third-party entity that manages and holds operational responsibilities for cloud-based data backup services and solutions to customers from a central data center.
- CSB: Typically a third-party entity or company that looks to extend or enhance value to multiple customers of cloud-based services through relationships with multiple CSPs. It acts as a liaison between cloud services customers and CSPs, selecting the best provider for each customer and monitoring the services. The CSB can be utilized as a "middleman" to broker the best deal and customize services to the customer's requirements.
May also resell cloud services.
- Cloud service auditor: Third-party organization that verifies attainment of SLAs.