a. all present-day organisms have descended, with adaptations, from one--or possibly a few--original organisms
b. Earth's history has been marked by several periods when destruction of populations was widespread and that, after each such period, the earth was repopulated
c. evolutionary changes in organisms are caused by use and disuse
d. although evolution is responsible for all the changes that happen to species, one center of creation resulted in
the original members of each species
e. geologic processes in Earth have not changed over billions of years
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