Final answer:
Rabbits and kangaroos, and whales and fish, are the most distantly related pairs evolutionarily because despite similar physical traits, their lineages diverged millions of years ago and they belong to different evolutionary paths.
Step-by-step explanation:
Rabbits and kangaroos and whales and fish are the pairs that are least alike or most distantly related evolutionarily. While the pairs share certain morphological features, such as powerful jumping legs for rabbits and kangaroos, and a similar body shape for whales and fish, they have a significantly different evolutionary background.
Particularly, whales and fish would appear to be more closely related due to their aquatic lifestyles and body shapes; however, whales are mammals and share a more recent common ancestor with other mammals, such as horses, rather than with fish. Therefore, in an evolutionary context, rabbits and kangaroos, which both developed powerful jumping legs after their lineages split over 150 million years ago, and whales and fish, which converge morphologically but diverged about 400 million years ago when fish and mammals went separate evolutionary pathways, are the least genetically similar.