Unlike animal cells, plant cells have and unlike plant cells, animal cells have select one or more: a. chloroplasts; cell walls; a nucleus b. centrioles; chloroplast; cell walls c. centrioles; cell walls; large central vacuoles d. chloroplasts; cell walls; centrioles

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).

colors do exist. the color of the sky is actually violet; humans percieve the color of the sky as blue.

sound moves fastest in solids because the molecules are tightly packed and it allows sound to vibrate