Question

genetic modification of food crops is considered controversial because
o some people worry it will negatively impact human health.
o farmers worry that genetically modified crops will not be hardy.
o some people are afraid they will not like the taste of modified foods.
o farmers are afraid it will make their crops more susceptible to pests.

Explanation:

Genetic modification of food crops is controversial mainly due to concerns about its impact on human health. There are worries that it may have unforeseen negative effects on consumers. While other concerns like crop hardiness, taste, and pest - susceptibility exist, the human - health concern is a major factor.

Answer:

some people worry it will negatively impact human health.