The wing of a bat, the arm of a human, and the flipper of a whale are structurally different even though they have similar bone structure. what is the main reason for these structural differences?

Which of the following is the best definition of a eukaryota? a. a one-celled organism that does not have a membrane-bound nucleus b. a one-celled organism that does not have a cell wall c. an organism whose cells each contain a membrane-bound nucleus d. an organism whose cells each have a cell wall