Algae and nitrogen-fixing bacteria are photosynthetic organisms.
They hide in places like driftwood and vegetation
Answer:
Explanation:
(in an echinoderm) each of a large number of small flexible hollow appendages protruding through the ambulacra, used either for locomotion or for collecting food and operated by hydraulic pressure within the water-vascular system.
Cell theory was fdiscovered in the 17th century. but the first. cell theory was credited in the 19th century.