A stroke can result in a number of visual problems, including visual neglect, decreased visual acuity, diplopia (double-vision), squint, and homonymous hemianopsia (visual field defects).
Natural Selection. Natural selection is the process by which individuals with characteristics that are advantageous for reproduction in a specific environment leave more offspring in the next generation, thereby increasing the proportion of their genes in the population gene pool over time.
Natural selection looks for the best traits to fit the current environment of a species. Now, natural selection does not directly cause an adaptation. This is how it works: if â¦ a mutation causes a species to produce more surviving offspring that inherit that trait, than many many many generations down the line it would be considered an adaptation.