ReactJS Practice Test

React components are the building blocks of a UI. They’re small, reusable pieces of code that describe a part of the interface and render HTML (via JSX) for given inputs. A component can be a function or a class, and it can accept inputs called props and manage internal state to control what it renders. By composing multiple components, you build up complex interfaces from simple, isolated pieces.

That’s why the statement that best describes a React component is the one that frames it as a small, reusable chunk of code that renders HTML. An event handler is just a function responding to actions, not the component itself. A CSS stylesheet provides styling, not UI structure. A DOM node is the actual element created in the browser, not the reusable piece of code that defines how UI should look.