The word "afford" in the passage is closest in meaning toA．offerB．preventC．increaseD．remov

ncentrate minerals at levels a hundredfold or greater than normal. A survey of known hyperaccumulators identified that 75 percent of them amassed nickel; cobalt, copper, zinc, manganese, lead, and cadmium are other minerals of choice. Hyperaccumulators run the entire range of the plant world. They may be herbs, shrubs, or trees. Many members of the mustard family, spurge family, legume family, and grass family are top hyperaccumulators. Many are found in tropical and subtropical areas of the world, where accumulation of high concentrations of metals may afford some protection against plant-eating insects and microbial pathogens.

Why does the author mention "herbs," "shrubs," and "trees"?

A．To provide examples of plant types that cannot tolerate high levels of harmful minerals

B．To show why so many plants are hyperaccumulators

C．To help explain why hyperaccumulators can be found in so many different places

D．To emphasize that hyperaccumulators occur in a wide range of plant types

The word "suspended" in the passage is closest in meaning to

A．grown

B．protected

C．spread out

D．hung

ficiencies in plants?

A．It allows researchers to control what nutrients a plant receives.

B．It allows researchers to observe the growth of a large number of plants simultaneously.

C．It is possible to directly observe the roots of plants.

D．It is unnecessary to keep misting plants with nutrient solutions.

that is, in soilless liquid nutrient solutions. This technique allows researchers to create solutions that selectively omit certain nutrients and then observe the resulting effects on the plants. Hydroponics has applications beyond basic research, since it facilitates the growing of greenhouse vegetables during winter. Aeroponics, a technique in which plants are suspended and the roots misted with a nutrient solution, is another method for growing plants without soil.

The word "facilitates" in the passage is closest in meaning to

A．slows down

B．affects

C．makes easier

D．focuses on

According to paragraph 2, a symptom of iron deficiency is the presence in young leaves of

A．deep red discoloration between the veins

B．white or yellow tissue between the veins

C．dead spots between the veins

D．characteristic dark green veins

lants but not in plants deficient in nitrogen or iron?

A．Chlorosis on leaves

B．Change in leaf pigmentation to a dark shade of green

C．Short, stunted appearance of stems

D．Reddish pigmentation on the leaves or stem

chlorophyll resulting in yellow or white leaf tissue), necrosis(isolated dead patches), anthocyanin formation(development of deep red pigmentation of leaves or stem), stunted growth, and development of woody tissue in an herbaceous plant. Soils are most commonly deficient in nitrogen and phosphorus. Nitrogen-deficient plants exhibit many of the symptoms just described. Leaves develop chlorosis; stems are short and slender; and anthocyanin discoloration occurs on stems, petioles, and lower leaf surfaces. Phosphorus-deficient plants are often stunted, with leaves turning a characteristic dark green, often with the accumulation of anthocyanin. Typically, older leaves are affected first as the phosphorus is mobilized to young growing tissue. Iron deficiency is characterized by chlorosis between veins in young leaves.

The word "exhibit" in the passage is closest in meaning to

A．fight off

B．show

C．cause

D．spread

Listen to Track 11.

A．Other students should comment on the man"s remark.

B．Most people would agree with the man"s opinion.

C．Artwork funded by the government is usually of excellent quality.

D．The government project was not a waste of money.

What does the professor say about artists opinions of government support for the arts?

A．Most artists believe that the government should provide more funding for the arts.

B．Most artists approve of the ways in which the government supports the arts.

C．Even artists do not agree on whether the government should support the arts.

D．Even artists have a low opinion of government support for the arts.

Why does the professor mention the Kennedy Center and Lincoln Center?

A．To give examples of institutions that benefit from corporate support

B．To illustrate why some artists oppose the building of cultural centers

C．To show how two centers were named after presidents who supported the arts

D．To name two art centers built by the government during the Depression