Why are differences and similarities in DNA and proteins evidence of evolution?

Homologous structures provide evidence for common ancestry analogous structures show that similar selective pressures can produce similar adaptations beneficial features Similarities and differences among biological molecules in the DNA sequence of genes can be used to determine species relatedness

the cladogram shown here shows similarities and differences among several classes of vertebrates. anatomically, the four have limb structure as their common ancestor. we might separate the mammals from the other three classes because they a) divergent; do not lay eggs b) identical; are warm-blooded c) varied; a four chambered heart d) homologous; have mammary glands

registered nurse (rn): the rn is responsible for carrying out both the medical plan of care prescribed by the physician as well as the nursing care plan developed by the nursing staff. the rn assesses each resident and modifies the nursing care as needed to meet the patient's needs.