New Vocabulary

2. the political and economic theories of Karl Marx and Friedrich Engels, later developed by their followers to form the basis of communism.
4. a substance used for killing insects.
6. a process by which molecules of a solvent tend to pass through a semipermeable membrane from a less concentrated solution into a more concentrated one.
7. animal dung used for fertilizing land.
8. a piece of equipment or furniture which is fixed in position in a building or vehicle.
11. (of a bacterium, virus, or other microorganism) causing disease.
13. individuals' belief that they cannot control what happens to them.
15. bacteria that oxidize organic compounds to acetic acid, as in vinegar formation.
17. excessive richness of nutrients in a lake or other body of water, frequently due to run-off from the land, which causes a dense growth of plant life.
19. prejudice or discrimination against someone based on their age.
21. very skilled or proficient at something

1. make (a doubt, feeling, or belief) disappear.
3. a nitrogen-fixing bacterium that is common in the soil, especially in the root nodules of leguminous plants.
5. the arrangement or classification of something into different groups.
9. a small ornament or item of jewellery that is of little value.
10. a closed stratification system traditionally found in India.
12. a substance that is toxic to plants, used to destroy unwanted vegetation.
14. pleasure, especially when gained from the satisfaction of a desire.
16. a system of methods used in a particular area of study or activity.
18. having or showing high moral standards.
20. elating to or characteristic of a microorganism, especially a bacterium causing disease or fermentation.