PETERSON TOEFL TEST PRACTICE 1 PART 6

QUESTIONS 19-30

Many flowering plants woo insect pollinators and gently direct them to their most fertile blossoms by changing the color of individual flowers from day to day. Through color cues, the plant signals to the insect that it would be better off visiting one flower on its bush than another. The particular hue tells the pollinator that the flower is full of far more pollen than are neighbouring blooms. That nectar-rich flower also happens to be fertile and ready to disperse its pollen or to receive pollen the insect has picked up from another flower. Plants do not have to spend precious resources maintaining reservoirs of nectar in all their flowers. Thus, the color-coded communication system benefits both plant and insect.

For example, on the lantana plant, a flower starts out on the first day as yellow, when it is rich with pollen and nectar. Influenced by an as-yet-unidentified environmental signal, the flower changes color by triggering the production of the pigment anthromyacin. It turns orange on the second day and red on the third. By the third day, it has no pollen to offer insects and is no longer fertile. On any given lantana bush, only 10 to 15 percent of the blossoms are likely to be yellow and fertile. But in rests measuring the responsiveness of the butterflies, it was discovered that the insects visited the yellow flowers at least 100 times more than would be expected from haphazard visitation. Experiments with paper flowers and painted flowers demonstrated that he butterflies were responding to color cues raher than, say, the scent of the nectar.

In other types of plants, blossoms change from white to red, others from yellow to red, and so on. These color changes have been observed in some 74 families of plants.

1.        The first paragraph of the passage implies that insects benefit from the color-coded communication system because

a)         the colors hide them from predators

b)        they can gather pollen efficiency

c)         the bright colors attract fertile females

d)        other insect species cannot understand the code

2.        The word woo n line 1 closest in meaning to

a)         frighten

b)        trap

c)         deceive

d)        attract

3.        The word it in line 3 refers to

a)         a plant

b)        an insect

c)         a signal

d)        a blossom

4.        The word hue in line 3 is closest in meaning to

a)         smell

b)        texture

c)         color

d)        shape

5.        The word thus in line 7 is closest in meaning to which of the following?

a)         However

b)        Therefore

c)         Probably

d)        Generally

6.        Which of the following describes the sequence of color changes that lantana blossoms undergo?

a)         Red to yellow to white

b)        White to red

c)         Yellow to orange to red

d)        Red to purple

7.        The word triggering in line 11 is closest in meaning to

a)         maintaining

b)        renewing

c)         limiting

d)        activating

8.        The passage implies that insects would be most attracted to lantana blossoms

a)         on the first day that they bloom

b)        when they turn orange

c)         on the third day that they bloom

d)        after they produce anthromyacin

9.        According to the passage, what is the purpose of the experiments involving paper flowers and painted flowers?

a)         To strengthen the idea that butterflies are attracted by the smell of flowers

b)        To prove that flowers do not always need pollen to reproduce

c)         To demonstrate how insects change color depending on the type of flowers they visit

d)        To support the idea that insects respond to the changing color of flowers.

10.    The word haphazard in line 15 is closest in meaning to which of the following?

a)         Dangerous

b)        Random

c)         Fortunate

d)        Expected

11.    What is known from the passage about the other types of plants mentioned in line 18?

a)         They follow various sequences of color changes

b)        They use scent and other methods of attracting pollinators

c)         They have not been studies as thoroughly as the lantana

d)        They have exactly the same pigments as the lantana

12.    According to the passage, in approximately how many families of plants has the color-changing phenomenon described in the passage been observed?

a)         10

b)        15

c)         74

d)        100

ANSWER  KEY

1.        B

According to the first paragraph, the changing colors of the blossoms tell insects which blossoms are full of pollen. Since the insects do not have to visit each blossom, they can gather pollen more efficiently.

2.        D

The word woo means attract, allure.

3.        B

The reference is to an insect.

4.        C

The word hue means color, shade.

5.        B

The word thus means therefore, consequently.

6.        C

A flower on the lantana plan “starts out …..as yellow” (lines 11-12) but “turns orange on the second day and red on the third” (lines 14-15)

7.        D

The word triggering means activating, stimulating.

8.        A

According to the passage £a flower starts out on the first day as yellow” (lines 11-12) and “insects visited the yellow flowers at least 100 times more than would be expected form haphazard visitation” (lines 18-20). Clearly, the flowers are most attractive to the insects on the first day.

9.        D

Linnes 20-22 indicate that the purpose of the experiments was to show that insects were responding to colors rather than to other stimuli, such as the scent (smell) of the nectar.

10.    B

The word haphazard means random, arbitrary.

11.    A

Lines 23-24 say that “in other types of plants, blossoms change from white to red, others from yellow to red, and so on.” This indicates that these plants follow a variety of color-change sequences.

12.    C

According to the passage, the phenomenon has been seen in “74 families of plants” (line 25).