Reading passages

15. The author points out that a 10 percent increase in human skin
cancer would be likely to occur .

1. 
   unless measures could be found to prevent ozone layer depletion
   
2. 
   should there be 20 percent increase in ultraviolet radiation
   
3. 
   if there were a 5 percent drop in the ozone layer density
   
4. 
   if ^rgent action were not taken to prevent it
   

E) as long as they don't use preventive lotions

There are several kinds of dams. One kind is called an earth dam. This consists of a large bank of earth with steep sides. Along the length of the base of the dam a cut-off wall is constructed and this extends down to an impervious stratum. The function of the cut-off wall is to make the foundation watertight. Openings are made in the base of the dam to allow water to escape, thus controlling the level of water in the reservoir and providing a regular supply of water. These openings are called sluices. There is one disadvantage with this kind of dam. The material does not become watertight until the reservoir is full of water.

16. The passage describes, in broad terms, .

1. 
   a number of disadvantages related to earth dams
   
2. 
   the advantages of various types of dams
   
3. 
   the differences between the various types of dams
   
4. 
   the technical features of an earth dam
   

E) common features of dams
17. According to the passage, the function of sluices in an earth dam is to_______ .
A) prevent any escape of water

2. 
   provide support for the cut-off wall
   
3. 
   direct the flow of incoming water
   
4. 
   maintain a regular supply of water in the reservoir.
   

E) leak wter when needed


18. It can be understood from the passage that, without a cut-off wall,

1. 
   an earth dam would not be water- tight
   
2. 
   it would be impossible to open sluices
   
3. 
   only an earth dam can be constructed
   
4. 
   a longer base would be essential for the functioning of an earth dam
   
5. 
   there will be no water shortage
   

Protoplasm, which is the fundamental basis of life, is constantly undergoing physical and chemical change. Life, therefore, is the resultant of these constantly occurring changes. There are two great groups into which living things may be classified plants and animals. Both the plant and the animal kingdoms are very extensive. It is customary, therefore, to regard the science of life under two comprehensive heads, namely, botany which is the study of plants and zoology, which is the study of animals. Both subjects are subdivided into various specialized sections.