5. Myth: Mammals and plants don't belong in the same domain.

Yes, this is a myth, as mammals and plants are both eukaryotes at the end of the day, meaning that they share a multitude of common characteristics. These characteristics include a size generally larger than prokaryotes, DNA enveloped by a membrane-surrounded nucleus, membrane-bound organelles, undergoing of complex processes like cellular respiration, presence of a cytoskeleton, linear DNA with histones, DNA with introns, undergoing of mitosis/meiosis, etc.