Across
- 2. Planktonic unicellular organisms
- 7. Planktonic marine protozoans that secrete glass skeletons
- 12. Star-shaped internal skeleton made of silica
- 15. Obtain energy from organic matter by respiration
- 17. Protozoans with hair-like cilia for locomotion and feeding
- 18. Derive energy form chemical compounds, not light
- 19. Known as blue-green algae, important for producing O2
- 20. Contain chlorophyll or other photosynthetic compounds
Down
- 1. Mostly aquatic and mostly photosynthetic (do not leave a space between the words)
- 3. Smallest of true living organisms and oldest forms of life
- 4. Make own organic compounds
- 5. Marine protozoans with calcium carbonate shell
- 6. Enclosed in cell walls made of silica - asexual reproduction
- 8. Massive calcareous mounds formed by Cyanobacteria
- 9. Simplest, most primitive life forms - small, spherical, spiral, or rod-shaped cells
- 10. Flagellated, spherical cells of calcium carbonate
- 11. Reproduce by infecting living cells
- 13. Converting gaseous Nitrogen (N2) to ammonium (NH4+1) do not leave a space between the words
- 14. Structurally simple, Eukaryotic organism
- 16. Found everywhere and on almost every surface