Sharks, whales, and dolphins share similar features such as body shape and the position of fins. However, sharks have gills for breathing, while whales and dolphins have lungs. These differences indicate that the organisms share a common ancestor for(blank) Whales also possess a vestigial pelvic bone. The presence of the pelvis bone may indicate that whales(blank) Blank 1 -body structure, but their breathing structures evolved from different ancestors -both body structure and breathing structure8s -breathing structures, but their body structure evolved from different ancestors Blank 2 -have legs inside their bodies -evolved from organisms with legs -will have legs in the future