Final answer:
The Stamp Act came into effect in 1765 and was met with resistance from the colonists.
Step-by-step explanation:
The act that came into effect in 1765 was the Stamp Act. It was an act imposed by the British Parliament on the American colonies, requiring them to pay a tax on various paper goods. The Stamp Act was met with strong resistance from the colonists, including boycotts, protests, and the formation of organizations like the Sons of Liberty.