<span>B. A prokaryotic cell does not have nucleus and the other one does. The most defining characteristic of eukaryotic cells is their true nucleus. Prokaryotes lack true nucleus</span> and membrane bound organelles.
Quite sure C is correct ;) remember that humans are also placental mammals.
<span>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)</span>
