Final answer:
It is true that underscores are acceptable in addition to alphabetic and digit characters in programming identifiers, but dashes and periods are not usually allowed.
Step-by-step explanation:
In the context of programming, the statement that in addition to alphabetic and digit characters, it is acceptable to use underscores, dashes, and periods as part of an identifier is partially true. While underscores are universally accepted in programming language identifiers, dashes and periods are not typically allowed. Identifiers can begin with a letter or an underscore and may be followed by letters, underscores, or digits. However, using dashes is usually not permitted because a dash is often interpreted as a minus operator in many programming languages. Periods are also not typically used within identifiers, as they are generally reserved for accessing attributes or properties in objects.