72. introducción . el principal problema que enfrenta la humanidad es la contaminación del agua, suelo y aire, pérdida de la biodiversidad, angustia social por enfermedades, de- sertificación, cambio climático, lo cual presiona a pro- fundizar la crisis del sistema agroalimentario global, por el uso excesivo de recursos no renovables, agro- tóxicos y monocultivos que han generado pobreza.

Unk the , . of and in " a to was is ) ( for as on by he with ‘s that at from his it an were are which this also be has or : had first one their its new after but who not they have.