Final answer:
B. False. Highlands in northeastern Washington state are not typically referenced as such; it is more accurate to associate the term with western regions of the U.S. The Southeastern U.S. was an independent center for plant domestication, and not all tribes of the Iroquois Confederacy remained neutral during the Revolutionary War.
Step-by-step explanation:
The statement about highlands located in the northeastern Washington is false. Highlands in the United States are generally found in the western part of the country, including the Rocky Mountains and the Sierra Nevada. The northeastern part of Washington state is characterized by a diverse landscape, which includes part of the Rocky Mountains and the Columbia Plateau, but is not typically referred to as the highlands.
The present-day Southeastern United States was indeed one of the world's independent centers for plant domestication, which is true. Early Native American societies in this region developed agriculture with the cultivation of crops like squash, sunflowers, and marsh elder.
Regarding the Iroquois Confederacy during the Revolutionary War, the statement that all of the tribes maintained neutrality is false. The confederacy was split, with some tribes supporting the British while others sided with the American colonists.