"three sisters" farming was an agricultural system of companion planting innovated by the iroquois-speaking peoples of the northeast; farmers planted corn, beans, and squash together. the beans used the cornstalks as a trellis to grow on, but how did beans benefit the other two plants in the system?
choose 1
a) bean shoots reached out and strangled weeds, leaving the way clear for other companion plants
b) bean leaves provided crucial shade for the squash, which can be damaged by to much sunlight
c) bacteria on the roots of beans "fix" nitrogen from the atmosphere into the soil, fertilizing the earth