The process by which a cell in culture acquires the ability to divide indefinitely, similar to the division of cancer cells ; or a change in genotype and phenotype due to the assimilation of external DNA by a cell . When the external DNA is from a member of a different species, transformation results in horizontal gene transfer:

What makes the results of a scientific experiment accurate? a) having multiple trials b) lacking any supporting data c) working in a lab d) using a hypothesis that is always true

Over the past 60 years, many amphibian species have experienced significant population declines and some species have become extinct. scientists suspected that local human activities such as the destruction of wetlands, regional pollution, and deforestation were the main reasons for these losses. however, research over the past 20 years reveals significant amphibian population declines in protected areas of the world, such as nature preserves and parks. these global declines suggest widespread problems including increased ultraviolet radiation, acid rain, and disease. in switzerland, for example, 14 of the 20 native amphibian species are threatened with extinction. chytridiomycosis is a fungal disease first identified in 1998 as a cause of massive amphibian deaths. in some severely impacted populations, a few individuals have survived, perhaps because of some natural resistance. if these resistant individuals continue to survive and prosper, new resistant populations might emerge. this would be an example of the founder effect artificial selection genetic drift natural selection sexual selection

Common symptoms of an iron-defiency anemia include muscle weakness shortness of breath and lightheadedness why does iron deficiency causes these symptoms