What are the four jobs a comma does on the ACT?

Separate a series, set off a nonessential element, follow an introductory element, and join clauses with a coordinating conjunction

What is the most common unnecessary comma the ACT plants?

A comma between a subject and its verb

Expand the contraction: 'it's' means 'it is' or 'it has'; 'its' is the possessive with no apostrophe

The opening and closing marks of a set-off element must be the same kind

To introduce an explanation or emphatic phrase after a complete independent clause

A period, because it is a statement reporting a question

A direct question, so it ends with a question mark

No, because 'and' joins two verbs that share one subject, not two independent clauses

The least-punctuated option that is still correct, because the ACT plants extra marks more often than it omits needed ones

12questions. Pick an answer and you'll see why right away.

What are the four jobs a comma does on the ACT?
What is the most common unnecessary comma the ACT plants?
How do you tell 'its' from 'it's'?
How is the plural possessive of 'dog' formed when several dogs own something?
What must come before both a colon and a semicolon?
Which correctly introduces a list: 'She packed three things ___ a map, a compass, and a flashlight'?
What is the matching-pair rule for dashes and parentheses?
When can a single dash be used like a colon?
What end punctuation does an indirect question take, such as 'She asked whether it was open'?
Is 'Can you tell me where the station is' a statement or a direct question?
Should there be a comma before 'and' in 'She baked the bread and sliced it'?
When options differ mainly in how many punctuation marks they add, which is usually safest on the ACT?