In React, the useEffect hook is used to perform side effects in functional components. Side effects can include data fetching, subscriptions, manual DOM manipulations, and other operations that cannot be handled during the render phase. The useEffect hook is called after the component has rendered, and it runs the specified function (the effect) that can contain code with side effects. Here’s a basic example to illustrate its usage: import React, { useEffect, useState } from 'react'; function E...