Inside a greenhouse, different types of trees are kept at 3 different humidity levels. These are left for 3 years. One tree is left outside in normal conditions. The heights of the trees are measured once a week

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