Final answer:
The statement that modern life has eliminated opportunities for natural selection in human populations is false. Natural selection persists albeit with different pressures such as dietary changes and new societal factors influencing survival and reproductive success.
Step-by-step explanation:
The statement that modern life in affluent countries such as the United States has completely removed opportunities for natural selection to act on human populations is False. Natural selection continues to shape human populations, although the pressures may have changed due to modern lifestyles.
While it is correct that modern human civilizations with their advanced technologies and lifestyles present new challenges and environmental conditions, this does not mean that natural selection ceases to exist. There have been a relaxation of some selection pressures from the hunter-gatherer environment and the emergence of new pressures, such as those from the advent of farming. For example, we've seen genetic adaptations like the ability of adults in some populations to digest lactose, which is directly tied to farming and the consumption of bovine milk.
Moreover, humans are still subject to the basic mechanics of evolution: different survival and reproductive success depending on genetic makeup. Social and environmental factors, combined with personal choices, continue to influence these variables, maintaining the process of natural selection despite modern advances.