Bearman and Brueckner (2001) found that teens who made a public virginity-until-marriage pledge became likely to remain sexually abstinent than similar teens who do not make the pledge.

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Explanation:

Bearman and Brueckner (2001) performed a survey and they found that teens who made a public virginity-until-marriage pledge became more likely to remain sexually abstinent than similar teens who do not make the pledge.

This was because they would strive to follow through to the public pledges they made whereas those who didn’t had no obligation to fulfilling any pledge.

i would say b. research typically uses a variety of sources

q1: artillery

q2: simon bolivar

q3:   their workers and farmers demanded a return to spanish rule.

q4: drafted new constitutions

q5: oligarchies have replaced monarchies