Final answer:
Artificial selection is exemplified by selective cow breeding for higher milk production, while natural selection is demonstrated by bacteria developing antibiotic resistance. Other examples given don't fit as cleanly into these categories, such as the feral dogs potentially showing natural selection, while genetically modified plants represent a different form of human-induced change.
Step-by-step explanation:
Among the given examples, the following can be described as evolution through artificial selection: A group of farmers selectively breed cows with the highest milk production (Example 2). This is a clear case of humans choosing specific traits to propagate in future generations of livestock, similar to how dog breeds have been developed.
Natural selection is illustrated by the evolution of bacteria developing resistance to antibiotics (Example 3). When a population of bacteria is exposed to antibiotics, only the individuals with resistance traits survive and reproduce, leading to a population that is largely resistant to that antibiotic. This occurs without direct human intervention, as opposed to artificial selection.
The other examples given, such as the feral population of dogs becoming wolf-like (Example 1) and the genetically modified plants (Example 4), do not neatly fit into the categories of natural or artificial selection. The feral dogs could potentially show natural selection if changes are due to environmental pressures and not human intervention. However, genetic modification, while a form of human intervention, does not operate through a breeding process and is thus a separate category of human-induced evolutionary change.