JavaScript Object Notation (JSON) and Extensible Markup Language (XML) are the most commonly used data formats for the Representational State Transfer (REST) API and are typically implemented with caching for increased scalability and performance. Extensible Markup Language (XML) and Security Assertion Markup Language (SAML) are both standards for exchanging encoded data between two parties, with XML being for more general use and SAML focused on authentication and authorization data.
HTML is used for authoring web pages for consumption by web browsers

Explanation/Reference:
Explanation:
Rapid elasticity allows a cloud environment to automatically add or remove resources to or from a system or application based on its current demands. Whereas a traditional data center model would require standby hardware and substantial effort to add resources in response to load increases, a cloud environment can easily and rapidly expand to meet resources demands, so long as the application is properly implemented for it.

Explanation
NIST Special Publications 800-145 is titled "The NIST Definition of Cloud Computing" and contains definitions and explanations of core cloud concepts and components.