Herbicides, chemicals administered by farmers to kill weeds, have been hugely beneficial in increasing the efficiency of modern agriculture. Many of the herbicides used today, however, are less effective than when they were originally introduced because weed populations have evolved resistance. Knowing this, which of the following statements is likely true?
Individual weeds that were able to adapt to the presence of herbicides survived, allowing the species to evolve.
The herbicides must negatively affect both the survival and reproductive ability of the weed species.
Herbicide resistance evolved because some species were able to outcompete other species in the presence of the herbicide.
Species that developed herbicide resistance must have had pre-existing heritable variation as to how likely they were to survive in the presence of an herbicide.
04:12
