Soil Formation
(1) How are granites, which are impregnable rocks, reduced to porous soil from which plants grow?
(2) Natural elements in our environment - water (as it reacts to heat and cold), wind, plants, and animals - are all powerful agents in the process of soil formation.
(3) Water is a formidable agent which can turn hard rock into pulverized soil. (4) The process begins when minerals in rocks expand unequally due to the heat of the sun. (5) Because of this uneven expansion, tiny cracks between minerals appear so that water seeps in. (6) Then with a drop in temperature the water freezes and expands resulting in terrific pressure pulverizing the surrounding rock.
(7) The wind also acts like water in converting rocks into soil. (8) It wears away solid rocks into bits. (9) If the wind blows, these fine rocks are transported to different directions.
(10) More than water and wind, the greater part of soil formation, is brought about by living plants and animals. (11) First, tiny lichens slowly appear on the surface of rocks and, in the process of metabolism, the rock continues to decay. (12) Later when thin soil begins to cover the rock, bigger plants take root, thus speeding up the soil formation process.
(13) Burrowing animals like worms also contribute to soil formation. (14) In fact, rich, porous soil comes from digestive tracts of worms which feed on organic minerals from rocks.
Comprehending the selection
Select the letter of the best answer.
1. The function of sentence 2 is
a. description
b. enumeration
c. comparison
2. The phrase The process in sentence 4 links the sentence to sentence 3 by referring the phrase to:
a. the noun - water
b. the verb phrase - turn hard rock
c. noun phrase - pulverized soil
3. Sentence 4 is linked to sentence 5 in a relationship of
a. cause-effect
b. comparison-contrast
c. condition-consequence
4. What word in sentence 5 is repeated in sentence 6 to relate the one to the other?
a. water
b. rock
c. pressure
5. The connective then shows that sentence 6 is linked to sentence 5 in a relationship of
a. comparison - contrast
b. action - sequence
c. cause - effect
6. Sentence 7 is linked to the preceding paragraph through
a. word repetition
b. connective
c. pronoun reference
7. The pronoun It in sentence 8 refers to
a. water
b. wind
c. rocks
8. Sentence 10 and sentence 11 are linked by
a. time relationship
b. comparison - contrast
c. general - specific
9. Sentence 13 is related to sentence 12 as
a. contrasting information
b. additional information
c. causal information