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CAMBRIDGE IELTS 10 – TEST 3 – PASSAGE 2

1. a description of the substance responsible for the red colouration of leaves.

Keywords: substance, red colouration, leaves

We need find the paragraph which features a substance making leaves red. In paragraph C, the author argues that “The source of the red is widely known: it is created by anthocyanins, water- soluble plant pigments reflecting the red to blue range of the visible spectrum”. Then, he described how this substance is created: “anthocyanins are actually newly minted, made in the leaves at the same time as the tree is preparing to drop them.”

=>ANSWER: C

1. the reason why trees drop their leaves in the autumn.

Keywords: trees drop leaves, autumn

In paragraph B, the writer indicates that “As fall approaches in the northern hemisphere, the amount of solar energy available declines considerably. For many trees-evergreen conifers being an exception-the best strategy is to abandon photosynthesis until the spring. So rather than maintaining the now redundant leaves throughout the winter, the tree saves its precious resources and discards them.”

• 
  autumn (British English)=fall (American English)
  

• 
  drop=discard
  

=>ANSWER: B

1. some evidence to confirm a theory about the purpose of the red leaves.

Keywords: a theory, purpose, red leaves.

In paragraph H: “Even if you had never suspected that this is what was going on when leaves turn red, there are clues out there.” Then, the writer provides 3 different clues explaining why leaves turn red.

• 
  evidence=clue
  

=>ANSWER: H

1. an explanation of the function of chlorophyll.

Keywords: function, chlorophyll.

In paragraph B, the writer argues that “summer leaves are green because they are full of chlorophyll, the molecule that captures sunlight and converts that energy into new building materials for the tree.”

=>ANSWER: B

1. a suggestion that the red colouration in leaves could serve as a warning signal.

Keywords: red colouration, warning signal.

In paragraph E, “It has also been proposed that trees may produce vivid red colours to convince herbivorous insects that they are healthy and robust and would be easily able to mount chemical defences against infestation.”

=>ANSWER: E

1. The most vividly coloured red leaves are found on the side of the tree facing the…

Keywords: most vividly coloured red, side, facing

In paragraph H, the writer says that “On many trees, the leaves that are the reddest are those on the side of the tree which gets most sun.”

• 
  the most vividly coloured red=the reddest
  

=>ANSWER: sun(light)

1. The …..surfaces of leaves contain the most red pigment.

Keywords: surfaces, most red pigment.

In paragraph H, the writer indicates that “Not only that, but the red is brighter on the upper side of the leaf”.

• 
  surface=side
  

=>ANSWER: upper

1. Red leaves are most abundant when daytime weather conditions are…..and sunny.

Keywords: abundant, daytime weather, sunny.

Also, in paragraph H, the writer argues that “It has been recognised for decades that the best conditions for intense red colours are dry, sunny days and cool nights…”

• 
  most abundant=the best conditions for intense red colours
  

=>ANSWER: dry

1. The intensity of the red colour of leaves increases as you go further…..

Keywords: red colour, increases, go further

In paragraph H, the writer says that “And finally, trees such as maples usually get much redder the more north you travel in the northern hemisphere.”

• 
  go further=the more (north) you travel
  

=>ANSWER: north

1. It is likely that the red pigments help to protect the leaf from freezing temperatures.

Keywords: red pigments, protect, freezing temperatures.

In paragraph F, the writer indicates that “It sounds paradoxical; because the idea behind this hypothesis is that the red pigment is made in autumn leaves to protect chlorophyll, the light- absorbing chemical, from too much light.” So, the statement is FALSE.

=>ANSWER: FALSE

1. The „light screen‟ hypothesis would initially seem to contradict what is known about chlorophyll.

Keywords: the light screen hypothesis, contradict, chlorophyll.

The „light screen‟ hypothesis is mentioned in paragraph F. “It (The hypothesis) sounds paradoxical, because the idea behind this hypothesis is that the red pigment is made in autumn leaves to protect chlorophyll, the light- absorbing chemical, from too much light.” Then, the writer raises a question:

“Why does chlorophyll need protection when it is the natural world‟s supreme light absorber?” So, this is a contradiction between the „light screen‟ hypothesis which supposes that chlorophyll is protected from too much light by the red pigment and what is known about chlorophyll (the natural world‟s supreme light absorber). The statement is TRUE.

• 
  seem to contradict=sound paradoxical
  

=>ANSWER: TRUE

1. Leaves which turn colours other than red are more likely to be damaged by sunlight.

Keywords: other than red, more likely, damaged by sunlight.

In this passage, the author does not mention whether leaves which turn colours other than red are more likely to be damaged by sunlight. In paragraph I, we read that some trees do not waste energy to produce red leaves, they simply show their natural orange or yellow colours, but no more information is given. So, the statement is NOT GIVEN.

• 
  colours=hues
  

=>ANSWER: NOT GIVEN

1. 
   For which of the following question does the writer offer an explanation?
   
2. 
   why conifers remain green in winter
   
3. 
   how leaves turn orange and yellow in autumn
   
4. 
   how herbivorous insects choose which trees to lay there eggs in
   
5. 
   why anthocyanins are restricted to certain trees
   

In paragraph B, the writer indicates that “For many trees-evergreen conifers being an exception- the best strategy is to abandon photosynthesis until the spring”. However, he does not explain why conifers remain green throughout the winter

1. 
   In paragraph C, the writer argues that “As chlorophyll is depleted, other colours that have been dominated by it throughout the summer begin to be revealed. This unmasking explains the autumn colours of yellow and orange…”
   
2. 
   At the end of paragraph E “No one has as yet ascertained whether more robust trees sport the brightest leaves, or whether insects make choices according to colour intensity.
   
3. 
   There are some theories about anthocyanins but they do not explain why anthocyanins are restricted to certain trees
   

=> ANSWER: B