What data type in ActionScript 3.0 represents a sequence of 16-bit characters?

The data type that represents a sequence of 16-bit characters in ActionScript 3.0 is the String type. Strings are used to handle textual data, and in ActionScript 3.0, they are specifically encoded in UTF-16, which allows for a wide range of characters, including those from various writing systems, emojis, and special symbols.

When working with strings, each character in the sequence is stored as a 16-bit unit, which is essential for general internationalization and to support the various characters outside the basic ASCII range. This representation makes it possible to manipulate text efficiently, allowing developers to perform operations such as concatenation, substring extraction, and search operations.

The other data types mentioned have different purposes: Numbers represent numerical values and can be integers or floating-point numbers, Booleans represent true/false values, and Null represents the absence of a value. These types do not handle character sequences, making String the only appropriate choice for representing a sequence of 16-bit characters.