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B. Gradualism

"Gradualism is an evolutionary model that refers to the tiny variations in an organism or in society that happen over time to make a better fit for animals and humans in their environment. These variations allow them to survive and thrive, resulting in the slow and consistent process of change in the whole population."

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

c. establishing proper sleep hygiene