Kaltura Share to Google Classroom Naturalist Rudy Mancke removes the spins of the sea urchin and explains what a test is. Grades: 3 4 5 6 7 8 9 10 11 12 Subjects: ScienceLife ScienceThe Animal KingdomInvertebrate Collection: ETV StreamlineSCRudy Mancke Collection Series: Short Takes with Naturalist Rudy Mancke