Q: Background: Active transport occurs when a substance passes through the cell membrane with the help of extra energy. This happens when a substance moves from an area where it is less concentrated to an area where it is more concentrated. This is the opposite of diffusion. The substance moves up, instead of down, the concentration gradient. Like rolling a ball uphill, this requires an input of energy. The energy comes from the molecule named ATP (adenosine triphosphate). The energy allows special transport proteins called pumps to move substances to areas of higher concentration. An example is the sodium-potassium pump. Paragraph: Two cells, Cell B and Cell C, are being examined under microscopes by students in a science class. While looking at the cells, one student, Kim, notices that there is a noticeable trend in Cell B for a particular substance to try to group up in a more concentrated area. In Cell C though, she notices that the same substance is spreading apart and finding less concentrated areas to move to. Given the paragraph above, please answer correctly the following question: Which cell is not exhibiting active transport?
A: Cell C

Q: Background: HIV , or human immunodeficiency virus, causes AIDS. AIDS stands for "acquired immune deficiency syndrome." It is a condition that causes death and does not have a known cure. AIDS usually develops 10 to 15 years after a person is first infected with HIV. The development of AIDS can be delayed with proper medicines. The delay can be well over 20 years with the right medicines. Today, individuals who acquire HIV after 50 years of age can expect to reach an average human life span. Paragraph: Two college buddies have known each other for 20 years. Tim was HIV positive while John was not and he didn't have a problem with it. Both friends are 40 years old. Given the paragraph above, please answer correctly the following question: Which friend can expect to reach an average human life span?
A: John

Q: Background: Wilting is the loss of rigidity of non-woody parts of plants. This occurs when the turgor pressure in non-lignified plant cells falls towards zero, as a result of diminished water in the cells. The rate of loss of water from the plant is greater than the absorption of water in the plant. The process of wilting modifies the leaf angle distribution of the plant (or canopy) towards more erectophile conditions. Lower water availability may result from: drought conditions, where the soil moisture drops below conditions most favorable for plant functioning; the temperature falls to the point where the plants vascular system can not function. high salinity, which causes water to diffuse from the plant cells and induce shrinkage; saturated soil conditions, where roots are unable to obtain sufficient oxygen for cellular respiration, and so are unable to transport water into the plant; or bacteria or fungi that clog the plant's vascular system. Wilting diminishes the plant's ability to transpire and grow. Permanent wilting leads to plant death. Symptoms of wilting and blights resemble one another. Paragraph: Jim had a small veggie garden that he planted every year. His brother Rob had a similar patch, and he was also a gardener. The plants in Jim's garden started wilting at some point and he found out that his soil had high salinity and some harmful bacteria that wiled the plants indirectly. Rob's plant were ok, because he adjusted the soil's ph with sweet lime. Given the paragraph above, please answer correctly the following question: Which garden soil had less bacteria and fungi problems?
A: Rob's

Q: Background: In addition to insects, weeds have also been a menace to farmers - just ask anyone with a garden how much they hate weeds. They can quickly compete for water and nutrients needed by other plants. Sure, farmers can use herbicides to kill weeds, but do these chemicals also harm the crops? Can biotechnology help with this issue? Some crops have also been genetically engineered to acquire tolerance to the herbicides - allowing the crops to grow, but killing the weeds. But the lack of cost effective herbicides with a broad range of activity - that do not harm crops - is a problem in weed management. Multiple applications of numerous herbicides are routinely needed to control the wide range of weeds that are harmful to crops. And at times these herbicides are being used as a preventive measure that is, spraying to prevent weeds from developing rather than spraying after weeds form. So these chemicals are being added to crops. This practice is followed by mechanical and/or hand weeding to control weeds that are not controlled by the chemicals. Crops that are tolerant of herbicides would obviously be a tremendous benefit to farmers ( Figure above ). The introduction of herbicide tolerant crops has the potential to reduce the number of chemicals needed during a growing season, thereby increasing crop yield due to improved weed management and decreased harm to the crops. Paragraph: Dan studied genetic engineering. He was applying his knowledge of genetic engineering to develop better crops. Recently, he had successfully developed a crop, crop A, that was herbicide tolerant. To determine the versatility of the crop he compared it with another crop that was not tolerant of herbicides, crop B. The results of his research would allow his company to market the new crop. Given the paragraph above, please answer correctly the following question: Would crop A have lower or higher yields than crop B?
A:
higher