Where did the arrival of General Zachary Taylor's troops spark the start of the Mexican-American War?

Palo Alto north of the Rio Grande River in Mexico

Explanation:

- three-quarters or two-thirds..

- "the constitution provides that an amendment may be proposed either by the congress with a two-thirds majority vote in both the house of representatives and the senate or by a constitutional convention called for by two-thirds of the state legislatures."

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