Answer: separate individual items in a list
Step-by-step explanation:
Colons are typically used after an independent clauses and they are used to draw attention to a particular thing or in the presentation of an explanation.
They can also be used to link two complete sentences together, express a ratio of two numbers and also follow the name of a person in business correspondence.
It should be noted that colons cannot be used to separate individual items in a list. That is the function of a comma.