Hi! Have you ever heard of reactJS? It's a JavaScript library for building user interfaces. 
No, I don't know much about programming. When was it invented?
It was first deployed on Facebook's news feed in 2011. 
Can it be used on iPhone or Android?
Yes. But it is called React Native. It enables native Android and iOS development with React. 
What are some of it's features?
It allows developers to create large web-applications that use data and can change over time without reloading the page. Like FB's newsfeed. 
Is it used in other applications that we use daily like Facebook?
React (JavaScript library)
React (also known as React.js or ReactJS) is a JavaScript library for building user interfaces. It is maintained by Facebook and a community of individual developers and companies.
React can be used as a base in the development of single-page or mobile applications, as it is optimal for fetching rapidly changing data that needs to be recorded. However, fetching data is only the beginning of what happens on a web page, which is why complex React applications usually require the use of additional
Redux (JavaScript library)
Redux is an open-source JavaScript library for managing application state. It is most commonly used with libraries such as React or Angular for building user interfaces. Similar to (and inspired by) Facebook's Flux architecture, it was created by Dan Abramov and Andrew Clark.
Description.
Redux is a small library with a simple, limited API designed to be a predictable container for application state. It operates in a similar fashion to a reducing function, a functional programming concept.