Which best describes activation energy? A. the maximum amount of energy required to end a chemical reaction
B. the amount of energy absorbed in an endothermic reaction
C. the minimum amount of energy required to start a chemical reaction
D. the amount of energy released in an exothermic reaction

Even though the ostrich is a flightless bird, ostriches still possess wings that stretch approximately two meters across when fully extended. scientists speculate that when dinosaurs became extinct, some of the birds that lived during that time became land dwellers since they were able to consume the food that the dinosaurs once ate. over time, these species grew larger and heavier. eventually, the ostrich species became too big to fly. the wings found on ostriches are known as a. analogous structures. b. homologous structures. c. vestigial structures. d. symmetrical structures.