Which of the following provides the best comparison between reptiles and fish?
They both have scales, but fish are ectothermic and reptiles are endothermic.
They are both ectothermic, but fish have gills and reptiles have lungs.
They are both vertebrates, but fish have three-chambered hearts and reptiles have two-chambered hearts.
They both lay eggs, but fish are invertebrates and reptiles are vertebrates.