HTML is the standard markup language used to create web pages, while HTML5 is the latest version that introduces semantic elements, multimedia support (audio and video), canvas, local storage, geolocation, and improved APIs without requiring additional plugins.

• HTML creates the structure of a webpage.
• CSS controls the design, layout, colors, fonts, and responsiveness.
• JavaScript adds interactivity such as sliders, forms, animations, validations, and dynamic content.

Responsive Web Design is the technique of designing websites that automatically adjust their layout according to different screen sizes such as desktops, tablets, and mobile devices using CSS Media Queries, Flexible Grids, and Bootstrap.

Bootstrap is a front-end CSS framework that helps developers build responsive and mobile-friendly websites quickly using a predefined grid system, components, and utility classes.

• An ID is unique and should be used only once on a page.
• A Class can be used multiple times for styling multiple elements.

WordPress is a Content Management System (CMS) used to create websites without extensive coding. It supports themes, plugins, custom post types, and allows users to manage website content easily.

PHP is a server-side scripting language used to build dynamic websites. It processes forms, interacts with databases, manages user authentication, and powers websites such as WordPress.

MySQL is a relational database management system used to store and manage website data such as user information, products, orders, blog posts, and application records.