Balance the following reaction. Choose "blank" if no coefficient is needed. C 2 H 5 + O 2 → CO 2 + H 2 O

Which of these statements is correct about plastic and concrete? a) both plastic and concrete are minerals because they are natural, solid materials. b) both plastic and concrete are not minerals because they are made by humans. c) plastic is a mineral because it has a definite crystal structure but concrete is not a mineral because it is organic. d) plastic is not a mineral because it is not formed under the ground but concrete is a mineral because it has a definite composition.