Final answer:
The obstacles to collective action are rational ignorance, small groups, and high levels of taxes.
Step-by-step explanation:
Collective action problems arise when people have a disincentive to take action. In this case, the obstacles to collective action are rational ignorance, small groups, and high levels of taxes. Rational ignorance occurs when people choose not to acquire information about an issue because they believe their individual actions will have little impact. Small groups make it easier to monitor individual behavior and exert peer pressure, thus reducing free riding. High levels of taxes can discourage individuals from taking action if they believe the costs outweigh the benefits. These obstacles can hinder collective action and make it difficult to mobilize a group for a common goal.