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

[Q]: Passage: Humans learn behaviors through conditioning, as well. A young child might learn to put away his toys by being rewarded with a bedtime story. An older child might learn to study for tests in school by being rewarded with better grades. Can you think of behaviors you have learned by being rewarded for them?. Answer: conditioning
[A]: How do humans learn behaviors?

[Q]: Passage: Although lots of symbiotic relationships help both organisms, sometimes one of the organisms is harmed. When that happens, the organism that benefits, and is not harmed, is called a parasite . This type of relationship is known as parasitism. Answer: parasite
[A]: Although lots of symbiotic relationships help both organisms, sometimes one of the organisms is harmed. when that happens, the organism that benefits, and is not harmed, is called a what?

[Q]: Passage: Chlamydia is the most common STI in the United States. As shown in the graph in Figure below , females are much more likely than males to develop chlamydia. Like most STIs, rates of chlamydia are highest in teens and young adults. Answer: chlamydia
[A]:
Which is the most common sti (sexually transmitted infection) in the united states?