microbial world

1. planktonic marine protozoans that secrete elaborate and delicate skeletons made of glass (silica) and other materials
4. a biologist who study microorganisms
5. Primary producers and consumers that drift with the currents
8. lies immediately inside the cell wall
10. short chain of genetic material
12. a highly resistant carbohydrate found in the skeleton of many animals, whereas it is made of cellulose in plants.
13. have a nucleus and several types of organelles
14. A sequence of nucleotides in the DNA molecule that directs the production of a particular protein
16. and the oldest forms of life on Earth
17. unicellular though many species aggregate into chains or star-like groups
18. A very diverse group of simple, mostly aquatic and photosynthetic organisms
19. the chemical reactions that take place in an organism

2. more closely related to eukaryotes than to bacteria
3. being formed in tropical seas
6. A complex carbohydrate characteristic of plants and other primary producers
7. Organisms that cannot make their own food and must sue the organic matter produced by autotrophs
9. have branched out very early on the tree of life and are genetically distant from both archaea and eukaryotes
11. protected by an outer protein
12. among the first photosynthetic organisms on Earth
15. live inside algae