(C) Enclosed
(D) Noteworthy
29. Which of the following was not mentioned as an activity performed as an activity performed on the front section of the pueblo?
(A) Cooking
(B)Sun tanning
(C) Making leather
(D) Weaving
30. It can be inferred that every level of the pueblo had a terrace
EXCEPT
(A) the second story
(B) the top story
(C) the first story
(D) the tird story
Questions 31-42
Hydroponics, the science of growing plants in water or inert substances, represents one of the most innovative practices in moden agricultural development. Not only does it allow greater precision of the plant growth process, it permits the production of crops in hostile in fertile environments.
The first widely publicized soilles gardeing experiments were conducted during the 1930's. W.F. Gericke, of the University of Califormai at Berkeley, varied nutrient levels among secimens suspended in a gravel substrate to demonstrate remarkable alterations in growth. Among the findings that amazed his fellow horticulturalists was the production of tomato plants over 6 meters high.
The original hydroponic gardens merely consisted of plants floating in water. It later discovered that the roots could survive in a number of media, as long as they were supplied with sufficeint moisture, nutrients and oxyen. Avariety of materials are used in recent versions including, gravel, sand, peat, sawdust, plastics and even peanut shells. Indeed, one of the most productive methods involes suspending plants in air with a styrofoam support and spraying them occasionally with nutrient solution to keep them moist.
Many different kinds of materials are suitable for physically containing plants, yet all of these systems share one trait: the culture solution. This nutrient bath is prepared in a tank by dissolving salts which provide the necessary chemicals for plant metabolism. Constant care must be taken to assure that the sodium-chloride levels in the tank do not reach excessive levels as the plants draw water and minerals out of the solution. The acidity of the tank must also be maintained aroudn 6.0 to 6.5 depending on the specific type of plants being harvested.
Although soilless farming is generally more expensive than utilizing fertile land, Herbicides and pesticides are unesessary becausue of the controlled environment. The plants also need less space to grow because their untrient uptake is significantly more efficient. The most outstanding benefit, though, is the ability to produce crops in areas with poor soil conditions or insufficient rainfall.
31. Which is NOT mentioned as a benefit of hydroponics?
(A) More control over plant growth
(B) Broader ranges of agricultural environements
(C) Production of impressive specimens
(D) Decreased costs compared to other methods
32. What does this passage mainly discuss?
(A) Soilless gardening
(B) Plant nutrition
(C) Growth media
(D) Controling plant growth
33. According to the passage, how did Gericke produce tall tomato plants?
(A) He altered the type of substrate.
(B) He demonstrated their growth to his fellow horticulturalists.
(C) He increased the acidity of their environment.
(D) He controlled their nutrition by growing without soil.
34. In line 8, the word "findings" is closest in meaning to
(A) outcomes
(B) questions
(C) verdicts
(D) convictions
35. Which of the following is NOT mentioned as a necessity for hydroponics?
(A) Moisture
(B) Nutrients
(C) Earth
(D) Oxygen
36. According to the passage, which part of the plant is most affected by the modern horticulture?
(A) Leaves
(B) Stems
(C) Roots
(D) Flowers
37. In line 11, word "media" is closest in meaning to
(A) commercials
(B) substances
(C) averages
(D) organizations
38. In line 15, the word "suspending" most closely means?
(A) Halting
(B) Revoking
(C) Hanging
(D) Removing
39. According to the passage, what quality do all soilless systems have in common?
(A) Gravel substrate
(B) Natural lighting
(C) Nutrient solution
(D) Similar results
40. Which of the following is NOT necessary to monitor in the nutrient solution?
(A) sodium-chloride levels
(B) Dissolved nutrient levels
(C) Acidity levels
(D) Proper substrate levels
41. According to the passage, what would be a good reason NOT to use hydroponics?
(A) Increased pesticides
(B) Produce
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