Over the Next Several Decades, World Population Growth Will Necessitate

Multiple Choice

Over the next several decades, world population growth will necessitate as much as a 60% increase in food production, primarily in developing countries. These countries are often the most seriously affected by drought and salinity. Even if irrigation water is available, flooding fields with irrigation water leads to the gradual accumulation of sodium ions and other salts in the soil.
To respond to this growing problem, scientists at the University of Connecticut have genetically engineered a plant that can survive in salty soil and withstand extended drought conditions. The new transgenic plant contains a gene for an ion pump. Salt ions are transported from the soil and stored in vacuoles in the cytoplasm. The enhanced uptake of ions into their vacuoles in turn improves water retention in the transgenic plants and their resistance to drought. The concentration of solutes inside and outside plant cells affects the direction of water movement through osmosis.
The researchers found that the salt concentration in the cells of the new transgenic plants was significantly higher than in wild plants used as a control. In addition, the transgenic plants survived longer when deprived of water.
-Planting these transgenic crops periodically would be beneficial to the environment because

A) the plants would help clean accumulated salts deposited in the soil by irrigation.
B) the transgenic plants would fix nitrogen and improve soil fertility.
C) the plants would remove carbon dioxide and decrease global warming.
D) the plants would resist diseases and decrease herbicide use.