Final answer:
An escape sequence begins with a backslash (\) and is used in programming to represent special characters within string literals, such as new lines (\\) and tabs (\t).
Step-by-step explanation:
An escape sequence always begins with a backslash (\). In programming, escape sequences are used to represent special characters within string literals that would otherwise be difficult or impossible to type directly. For example, \\ represents a new line, \t represents a tab, and \" is used to denote a double quote character without ending the string. These sequences are recognized by the compiler or interpreter to perform specific actions like moving to a new line or inserting a tab space.