Final answer:
The clearest indicator of the difference between a wild and a domesticated plant is the presence of traits in domesticated varieties that are favorable to human use, such as larger seeds and thinner husks, which arise from the process of artificial selection.
Step-by-step explanation:
What is the clearest indicator of difference between a wild and domesticated plant? The most evident differences stem from the process of domestication, whereby humans select plants with desirable traits and cultivate them to meet their needs. One clear example is the transformation of wild wheat and barley, which originally had heavy husks to protect the seeds, into varieties with thinner husks and more seeds, making them more suitable for human consumption.
These domesticated plants often exhibit characteristics like larger seeds, reduced protective structures, increased palatability, and sometimes a dependency on human intervention for successful growth and reproduction. Through artificial selection, humans have significantly altered plant species to the point where many domesticated versions would struggle to survive without agricultural support.
Comparing the wild ancestor teosinte to modern corn showcases the drastic changes that can occur through domestication. The domesticated corn has larger kernels that are more tightly clustered and easier to harvest, a striking contrast from the wild teosinte's smaller, spaced kernels.