Reading tests

54. The passage is concerned with the question of .

1. how the harmful effects of certain substances can be kept under control

   
   

1. why industrial waste streams have led to so much pollution

   
   

2. what measures are to be taken against the supply of dangerous substances

   
   

2. if man-made substances and natural ones cause pollution

   
   

E) who is responsible for taking the required precautions

The cheetah, the only mammal in the world that can sprint at spee faster than 70 miles per hour, is on rapid track to extinction. Two factc threaten its existence. The first is lack of genetic variation, which manife; itself in reproductive problems excessive infant mortality and vulnerability disease. These seem to be exacerbated in captivity, where cheetahs i experiencing a precipitous decline in number. The second threat to t cheetah is loss of its natural habitat to agricultural expansion.
55. The cheetah is the only mammal in the world that .

1. threatens the nature

   
   

2. is in danger of extinction

   
   

3. no other animals can reach its speed

   
   

D). has a speed reaching more than 70 miles per hour

E) is thought to give harm to agricultural expansion

56. The cheetah is threatened by extinction because .

1. of its speed

   
   

2. they are experiencing a sudden decline in number

   
   

3. of reproductive problems

   
   

D) they live in captivity

E) of lack of genetic differentiation and agricultural growth
57. Reproductive problems illustrate .

1. that cheetahs don't have a variation in their genetic structure

   
   

2. that the amount of infant mortality is excessive

   
   

3. cheetah is threatened by extinction

   
   

4. cheetah's vulnerability to disease

   
   

E) loss of their natural habitat leads them to extinction

When it was formed millions years ago the earth was a liquid. It is s having the process of cooling and many miles below the hard crust is s hot. However, in some places the heat is closer to the crust. These places i associated with volcanic activity or hot sulphur springs. Drilling deep ir the earth's crust we can reach rocks that are much warmer than those at t. surface. Pumping water down into contact with these rocks and extracting tl steam so produced is a source of energy that can be used to produi electricity. It is called geothermal energy.