TRIK JITU MENGERJAKAN SOAL TOEFL(READING)

      Lichens,of whicch more than twenty thousand species have been named,are complex associations between certain fungi and certain algae.The lichen itself is not an organism;rather it is the morphological and biochemical product of the association.Neither a fungus nor an alga alone can produce a lichen.

The intimate relationship between these two living components of a lichen was once erroneously thought to represent mutualism.In mutualistic relationships,both participants benefit.With lichens,however,it appears the fungus actually parasitizes the algae.This is one of the conclusions drawn from experiments in which the two components of lichens were separated and grown apart.

      The intimate relationship between these two living components of a lichen was one erroneously thought to represent mutualism.In mutualistic relationships,both participants benefit.With lichens,however,it appears the fungus actually parasitizes the algae.This is one of the conclusions drawn from experiments in which the two components of lichens were separated and grow apart.

      In nature,lichen fungi may encounter and grow around several kinds of algae.Some types of algae the fungi may kill;other types it may reject.Lichen algae algae are autotrophic,meaning they make their own food through photosynthesis.Lichen fungi are heterotrophic,meaning they depend upon the alge within the lichen to supply their food.Up to ninety percent of the food made by the the green alga cells is transferred to the fungus.What,if anything,the fungus contributes to the association is not well understand.

      Lichens are hardy.They grow in many habitats and are often pioneers in hostile environments where few other organisms can flourish.They have been known to grow endolithically,having been discovered thriving inside of rocks in Antarctica.Lichens help reduce erosion by stabilizing soil.Several kinds of insects glue lichens to their exoskeletons for camouflage.Many species of birds use lichens as building materials for nests.Human have used lichens for dyes and antibiotics.

1.Which of the following best describes the lichen association?

a.Simple plants made of two different autotrophic organisms

b.A mutualistic association between a fungus and an alga

c.A parasitic association netween two fungi,one autotrophic,the second heterotrophic

d.A union between a parasitic fungus and an autotrophic alga

pembahasan:Lichens are not considered to be plants,so choice(A)is incorrect.In mutualistic associations,both life forms benefit.The passage explains that the algae are parasitized in lichens,so choice(B)is incorrect.Choice(C)is wrong because the association is between a fungus and an alga,not two fungi.

2.The word"hardy"in line 23 is closest in meaning to

a.tender

b.durable

c.armed

d.benefical

pembahasan:The sentences following the sentence in which"hardy"is used describe some of the hostile places lichens can thrive,so you should realize that "hardy"means"tough,"or"durable."

3.In biology,mutualism occurs when two different organisms live close together and

a.onee organism parasitizes the other

b.both organisms benefit from the association

c.both organisms are harmed by the association

d.one organism benefits while the other does not or is harmed by the association

pembahasan:(B)The passage states that lichens were mistakenly thought to be mutualistic associations where both participants benefit,so choice(B)correctly defines the relationship.

4.In line 7,the word"intimate"is nearest in meaning to

a.living

b.extraordinary

c.biological

d.close

pembahasan:Any of the answer choices could describe the relationship of the fungi and algae in lichens;however,you should know that"intimate"means in "close"association.

5.Lichens serve as camouflage between the lichen components was clarified by

a.examining lichens with a microscope

b.observing lichens placed in the dark

c.observing the lichen components when groan apart

d.decreasing the amount of nutrients available to the lichens

pembahasan:In the last paragraph,it's explained that insects glue lichens on their exoskeletons for camouflage.

6.The true nature of the relationship between the lichen components was clarified by

a.examining lichens with a microscope

b.observing lichens placed in the dark

c.observing the lichen components when groan apart

d.decreasing the amount of nutrients available to the lichens

pembahasan:Paragraph 2 explains that lichens were once thought to represent mutualistic relationships,but this was tested by growing different lichen fungi and algae apart.

7.In line 24,the word"hostile"is closest in meaning to

a.unusual

b.cool

c.untraveled

d.inhospitable

pembahasan:According to the passage,a"hostile"environment is one in which few other organisms can flourish,so"inhospitable"would be the best answer.

8.An endolithic lichen is one that

a.grows in the canopies

b.grows inside rocks

c.grows at very high altitudes

d.grows inside other organisms,including other lichens

pembahasan:The sentence in which lichens are described as being endolithic goes on to explain that lichens have been found inside of rocks in America.

9.Many lichens contribute to the communities they inhabit by

a.removing pollutants from the air

b.controlling wood-rotting fungi

c.slowing the spread of viruses

d.reducing soil erosion

pembahasan:"Reducing so,erosion"is the only one of the four answer chouces that was stated in the reading passage.

10.In what part of the passage does the author indicate that scientists have changed their previous position on the makeup of lichens?

a.Lines 3-5

b.Lines 7-9

c.Lines 14-16

d.Lines 25-27

pembahasan:Paragraph 2 explains that experiments were conducted that showed the fungi parasitize the algae in the lichen relationship,but that this was not what scientists had originally thought.

reference:cliffs

toefl preparation guide

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