i. HTML (Hypertext Markup Language): deals with the content and interface structure of the app.
ii. CSS (Cascading Style Sheet) deals with the interface presentation, beatification and visual responsiveness of the HTML for example: images, font styles, font color, backgrounds etc.
iv. PHP (Hypertext Preprocessor) is a programming language that runs on the server side of the application in a centralized system.
v. SQL (Structured Query Language) is the language use to communicate with the database.