A is true because they do have a true nucleus or membrane-bound organelles .
Answer:
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).
Explanation:
Hope this helps.
Because it codes for specific proteins and contains the genetic instructions needed in order for an organism to survive, develop and reproduce
