Explanation:
1. By the, the observations that Joe found, he discovers a single celled organism, which shows various symptoms like; i) no pigmentation, ii) glassy looking, iii) porous shell or skeleton, iv) tiny extensions of cytoplasm extent in all directions and v) stiffened by thin rods, Joe concluded that, he is dealing with member of Rhizarians.
2. These all qualities show that it is a member of Rhizarians.