Given a scientific passage and an answer, generate a question for the given answer.

Passage: Figure 5.17 A uniporter carries one molecule or ion. A symporter carries two different molecules or ions, both in the same direction. An antiporter also carries two different molecules or ions, but in different directions. (credit: modification of work by "Lupask"/Wikimedia Commons). Answer: two
A symporter carries how many different molecules or ions in the same direction?