Outline how selective breeding has been used to improve wheat crops.
The heights of a strain of wheat plants in a field show a continuous pattern of variation. Explain what continuous variation means and explain why this kind of variation happens in a population.
Wheat and other crops have been genetically modified to resist the herbicide glyphosate since 1996. Fig. 4.1 shows the area of glyphosate-resistant crops grown as a percentage of the total planted hectares (plotted points) and the number of weed species resistant to glyphosate (bars). Describe and explain the relationship between the area of glyphosate-resistant crops grown and the number of resistant weed species.
Suggest one social advantage and one environmental advantage of cultivating glyphosate-resistant wheat.