They are found in some multicellular organisms, are associations of several tissues with an overall specialized function and they do not display all properties of life. All organisms are composed of one or more cells.
All cells come from pre-existing cells.
All cells are composed of one or more organisms and all organisms come from pre-existing organisms. Those individuals with heritable traits best suited to the local environment tend to be more successful at surviving and reproducing than are those individuals with heritable traits which are not as well suited to the local environment. A population of a species has the potential of producing more offspring than the environment can support with food, space and other resources. All of the above are key observations made by Charles Darwin. They form the hard part of bones.