Explain the syntax and usage of variables in Dart.

In Dart, variables are used to store and manipulate data within a program. They are fundamental components of any programming language and play a crucial role in storing values that can be accessed and modified throughout the execution of the program. Understanding the syntax and usage of variables in Dart is essential for effectively working with data and performing operations. Syntax: In Dart, variables are declared using the `var` keyword followed by the variable name, an optional type annotation, and an optional initial value. The general syntax for variable declaration in Dart is as follows: ``` dart`var variableName;` ``` or ``` dart`type variableName;` ``` or ``` dart`type variableName = initialValue;` ``` Usage: 1. Variable Declaration and Initialization: You can declare a variable without specifying its type explicitly by using the `var` keyword. Dart's type inference mechanism automatically determines the type bas....