Final answer:
The great American triad consisted of corn, beans, and squash. These crops were traditionally planted together by Indigenous peoples of North and Central America in a practice known as the "Three Sisters" technique.
Step-by-step explanation:
The great American triad consisted of corn, beans, and squash. These three crops were traditionally planted together by Indigenous peoples of North and Central America in a practice known as the "Three Sisters" technique. Corn provided a trellis for climbing beans, while beans fixed nitrogen in the soil, benefiting the growth of the other plants. Squash vines shaded out weeds and preserved moisture in the soil.