The idea that there is a high level of competition among the various religions in america seems to lead religions to work harder to attract more adherents. one of the main reasons causes for this competition is the

The correct answer is - the phenomenon of self-fulfilling prophecy.

Explanation:

Self-fulfilling prophecy is socio-psychological phenomenon during which an individual or a group of individuals shares a belief that a certain outcome is going to take place and this outcome takes place because their behavior and decisions align for this believe to come true.

Here, religious groups in America are aware of the idea that there is a high competition among them. Worrying that they are going to lose followers, they start to compete for new followers (behavior alignment) in order to keep the overall number of their followers.  

The other good example of a self-fulfilling prophecy is bitcoin bull runs. During the latest bull run of 2019, bitcoin price went up because certain amount of people shared rumors and expectation that it will.

this headline suggests that midterm congressional   elections are at the corner and trump administration wants to activate his base by vowing to clamp down on immigrants and immigration as trump had said during his election campaign around two years ago. when a baby is born in usa, the baby becomes citizen of usa for 85 years and trump wants to end this rule of birthright citizenship to control illegal immigration and this what he said in an interview""we’re the only country in the world where a person comes in and has a baby, and the baby is essentially a citizen of the united states for 85 years, with all of those benefits,” "

i honestly have no idea