Question

Human advances in medicine, shelter, and food production enable the survival of members of the population that might be weak or have traits not conducive to survival under primitive conditions. Therefore, they are able to reproduce in some cases, keeping deleterious genes in the gene pool. Why would this be considered to be working against the natural flow of evolution?

Answer 1

Normally natural selection remove these deleterious gene and individual carrying them but human advance protect those gene and individual ,so no loss of these traits .

Generally natural selection kill those individuals before they reproduce so that that deleterious trait not pass in next generation or keep individual carrying those trait sterile but human advance like medicine protect that individual so that trait also .So is against natural flow of evolution.