Final answer:
It is true that more than 70% of soybeans, corn, and cotton grown in the U.S. are genetically modified. The number exceeds 90% for soybeans with the 'Roundup Ready' variety.
Step-by-step explanation:
The statement that more than 70% of all soybeans, corn, and cotton grown in the United States are genetically modified is true. In fact, the percentage is even higher for certain crops. For instance, in the case of soybeans, more than 90% of soybean seeds planted in 2015 in the soybean-corn ecosystem of the central United States were from the genetically modified "Roundup Ready" variety. These crops have had changes introduced into their DNA using methods of biotechnology to introduce desirable traits, such as herbicide resistance. This technology allows for a variety of benefits in agricultural production, including control of weeds without damaging the crop. Furthermore, Genetic modifications are common in crops such as corn, which is a major agricultural crop often modified through plant biotechnology to create a variety of products for different industries.