Which term means organisms of a particular species no longer exist? 1. Petrified
2. Extinct
3. Novil
4. Endangered

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