What is the definition of survival of the fittest?

Compare the shapes of the bones of the human skull with the shapes of the bones of the human leg. how do the shapes differ? why are the shapes important?

The human body needs energy in order to carry out life processes such as breathing. where does the body get this energy? a. from eating food b. from learning about new things c. from lying in the sun d. from sleeping

Located at the epidermal-dermal junction of the skin. select all true statements about the transformation of melanocytes into abnormal cell