A. AIR B. SKY C. CLOUD D. WINDPART 3. READ THE FOLLOWING PASSAGE...
10. A. air
B. sky
C. cloud
D. wind
Part 3. Read the following passage and circle the letter A, B, C or D to indicate the
correct answer to each of the questions. (0.8 point)
All animal life on the planet Earth depends on a sufficient supply of oxygen for its day-
to-day survival. The trees that dot our landscapes provide a large portion of this supply: trees
take carbon dioxide from the surrounding air and in return they create a sizeable amount of
oxygen. Ironically, human beings, who cut down large numbers of trees to create land, shelter,
and energy, pose the most significant threat to the survival of the world-wide tree population.
But humans are not the only force that threatens the survival of these mighty members
of the plant kingdom. Trees, among the oldest and largest organisms on the planet, face many
other dangers. Lightning, fire, and other natural disasters, for example, can destroy many
square miles of old-growth forest in a matter of hours. Disease causing fungi and insect pests
can also eradicate entire populations of trees within a particular region.
After humans, however, the factor which most determines whether a particular
species of tree will prosper in a given area is climate. In particular, the amount of rainfall
and the range of temperatures that a region experiences strongly affects the distribution of
tree species.
All species of trees have evolved from plants that flourished many centuries ago in the
warm and wet tropical regions of the planet. As the distribution of trees has spread to other
regions, the differing climates of these regions have effectively limited the types of trees that
can live there. The greater the range of temperature and rainfall that a species of tree can
withstand, the more adaptable it is and therefore the wider its range of distribution.