England was pretty much broke after the French and Indian War, and to start getting money and paying back debts, they started taxing the American colonies. Some of the specific things they taxed were tea (which led to the Boston Tea Party), stamps, glass, lead, and paints that were imported into the colonies. All these taxes fell under the Townshend Acts.
When Europeans arrived in America in the 1600s, the frontiers began moving west. As they continued spreading their land occupation, American Indians were moved west. In 1889, the government transferred white colonists the Indian land, breaking the promise, as these lands had been promised to Indians. The Indians tried to take over those lands to no avail. In 1890 the Bureau of the Census stated there were no frontiers within the country.
As of modern day, false. It is closer to the 80s.
The other method of passing an amendment requires a Constitutional Convention to be called by two-thirds of the legislatures of the States. That Convention can propose as many amendments as it deems necessary. Those amendments must be approved by three-fourths of the states.