Question

since 2008, gmo crops have accounted for more than 80% of the corn and soybean crops planted in the u.s. corn (maize) seeds are modified with two genes: one kills insects that eat the seed, and one allows the seed to tolerate glyphosate, a herbicide commonly used in weed killers like roundup. soybeans are modified with just one glyphosate - resistant gene. since 2008, scientists at the university of virginia have been monitoring the effects of planting gmo corn and soybeans within farm ecosystems. the uva study found evidence that both corn and soybean farmers have increased herbicide use during the last five years, and the scientists concluded that planting these gmo crops is having a negative impact on the local environment. why? which choice does not provide a valid reason? a increased herbicide use results in increased contamination of aquatic ecosystems. b farmers resort to using additional chemicals as glyphosate - resistant weeds evolve. c the cultivation of gmos led to a significant increase of yield compared to the non - gmo varieties. d herbicides can have unintended consequences for non - target plant species thereby reducing plant biodiversity.

Explanation:

The question asks which option does not explain the negative environmental impact of GMO crops. Valid reasons link to environmental harm. Increased yield (Option C) is a positive outcome, not a negative impact.

Answer:

C. The cultivation of GMO's led to a significant increase of yield compared to the non-GMO varieties.