М. М. Кутепова The World of Chemistry Мир

Do you agree that Leo’s discovery is really interesting for science? Why?

Write a covering letter with the information about your contribution and request to invite you to participate in any of the gatherings mentioned in Unit 5, ex. 19. You can use some other words and expressions to write letters of this kind:

(1)
publication, reprint, material, copy
(2)
the paper, the material, the data


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(3)

to be held, to take place, to schedule, to fix
(4)
I’d like to, I’m very much interested in, I’m eager, I’mvery keen on
(5)
is worth being discussed/presented/listened to
(6)
I’m sending you, I have the pleasure of sending you For more information on useful expressions see Appendix 3.

REVISION AND DEVELOPMENT

UNITS 6 and 7

1. 
   Look through the following text and find the answers to the given questions:
   

1. 
   Who eats plants?
   
2. 
   What is the form of carbon in the Earth’s crust?
   
3. 
   What energy is used by green plants and algae and what do they do with it?
   
4. 
   What are the ways of forming carbon dioxide?
   
5. 
   How are human activities now estimated?
   
6. 
   Why is it hard now to estimate them?
   

It is known, that carbon, like water cycles from the Earth into the atmosphere and back again. Green plants and algae use the sun’s energy to convert carbon dioxide (and water) into carbohydrates. The -■ plants are eaten by animals, including people and fish, who exhale carbon dioxide. It was discovered that carbon dioxide is also formed by decomposition of dead animals and animal wastes by microorganisms. The carbon dioxide passes into the atmosphere and is again used for photosynthesis. An equilibrium also exists between carbon dioxide in the atmosphere and dissolved carbon dioxide and H₂C0₃ in oceans and lakes. In addition it was estimated that much carbon is stored in the Earth’s crust in the form of fossil fuels — coal, petroleum, and natural gas — and in the form of limestone and coral. Since the middle of the nineteenth century, it has been observed that the production of carbon dioxide by the combustion and the decomposition of limestones is increasing rapidly. In addition, it has been proved that destruction of tropical forests is reducing the quantity of carbon dioxide


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used up by photosynthesis. Human activities have now reached a scale where interference with the natural carbon cycle may well be significant. The longest continuous records of the concentration of C0₂ in the atmosphere unfortunately were made only in 1958, and therefore it’s hard to be sure how harmful human activities have been since that time.

2.