1. What is React.js primarily used for?
2. Who developed React.js?
3. Which programming language is commonly used to write React.js applications?
4. What is the term used to describe React's ability to update only changed parts of the user interface?
5. What is JSX in React.js?
6. Which virtual DOM library is used by React.js?
7. What is the primary function of ReactDOM in a React application?
8. In React, what are components?
9. What is the purpose of React Native?
10. Which of the following is NOT a core concept of React?