What are React applications made out of?

What are React applications made out of?

• A. HTML pages
• B. components
• C. functions
• D. events

Answer: (B)

React applications are built from components—small, reusable, self-contained pieces that describe a part of the user interface and can hold their own state and logic. The whole UI is created by composing these components together, so complex screens emerge from simpler building blocks. Components can be defined as functions or classes, and they return JSX that resembles HTML but actually describes what should render. This component-based model is what makes React so powerful: you can reuse components, manage their state independently, and pass data through props to customize how they behave. HTML pages exist in the browser, but in React you don’t assemble the app as static HTML; you declare the UI inside components that render HTML via JSX. Functions are used to implement the logic inside those components, and events are how you handle user interactions within them, but the essential unit of the app is the component itself.

React applications are built from components—small, reusable, self-contained pieces that describe a part of the user interface and can hold their own state and logic. The whole UI is created by composing these components together, so complex screens emerge from simpler building blocks. Components can be defined as functions or classes, and they return JSX that resembles HTML but actually describes what should render. This component-based model is what makes React so powerful: you can reuse components, manage their state independently, and pass data through props to customize how they behave.

HTML pages exist in the browser, but in React you don’t assemble the app as static HTML; you declare the UI inside components that render HTML via JSX. Functions are used to implement the logic inside those components, and events are how you handle user interactions within them, but the essential unit of the app is the component itself.