The nurse is assessing a patient who is malnourished and has a history of poor nutrition. the patient reports difficulty seeing at night. this patient is likely to be deficient in which fat-soluble vitamin?

genetic variation can be caused by mutation (which can create entirely new alleles in a population), random mating, random fertilization, and recombination between homologous chromosomes during meiosis (which reshuffles alleles within an organism's offspring).