they have a similar bone structure and they all have a common ancestor.
bone formation by osteaoblast
Not all animals have the same skeletal structure. Whales have bones in their "flippers" that resemble the same bones that make up the human "arm". This is called a homologous structure.
they all have a cell membrane
Ummm, no. The bones are what gives the body structure. Without them, we would be just a mass of featureless flesh.
Wings, hollow bones, and feathers.
The Skeletal system
The collection of bones in an organism is called the skeleton. The skeleton provides support, protection, and structure for the body.
Mitochondria
Cell walls !
Teeth because all animals need to chew their food.
Homologous structures in evolution refer to features that have a similar underlying structure, indicating a shared ancestry despite potentially different functions in different species. These structures are thought to have evolved from a common ancestor and provide important evidence for the theory of evolution. Examples include the pentadactyl limb structure in vertebrates and the similar bone structure in the wings of birds and the limbs of mammals.