Variables are used to store data in a program. They can store different types of data, such as numbers, text, or more complex data structures. Variables have a name and a value, and the value can be changed during the program's execution.

Arrays are a type of data structure used to store multiple values of the same type in a single variable. They can be thought of as a list or a collection of items. Arrays are useful when you need to store and manage a group of related values.

Operators are symbols used in programming languages to perform specific operations on values and variables. Some common operators include addition (+), subtraction (-), multiplication (*), and division (/). Operators can be used to manipulate data and perform calculations.

Conditional statements are used to make decisions in a program based on certain conditions. They allow the program to execute different blocks of code depending on whether a specific condition is true or false. Examples of conditional statements include 'if', 'else', and 'switch' statements.