microbial world

3. unicellular though many species aggregate into chains or star-like groups
4. more closely related to eukaryotes than to bacteria
6. lies immediately inside the cell wall
7. fixation converting gaseous nitrogen (N2), which is not available as nitrogen source to primary producers, into ammonium (NH4+1)
8. live inside algae
9. have branched out very early on the tree of life and are genetically distant from both archaea and eukaryotes
10. a biologist who study microorganisms
11. short chain of genetic material
14. among the first photosynthetic organisms on Earth
18. Primary producers and consumers that drift with the currents
19. protected by an outer protein
20. have a nucleus and several types of organelles

1. A sequence of nucleotides in the DNA molecule that directs the production of a particular protein
2. Organisms that cannot make their own food and must sue the organic matter produced by autotrophs
5. planktonic marine protozoans that secrete elaborate and delicate skeletons made of glass (silica) and other materials
12. being formed in tropical seas
13. a highly resistant carbohydrate found in the skeleton of many animals, whereas it is made of cellulose in plants.
15. and the oldest forms of life on Earth
16. A complex carbohydrate characteristic of plants and other primary producers
17. A very diverse group of simple, mostly aquatic and photosynthetic organisms