In several countries, to slow global warming, many farmers are planting trees on their land because of government incentives. These incentives arose from research indicating that vegetation absorbs carbon dioxide that might otherwise trap heat in the atmosphere. A recent study, however, indicates that trees absorb and store carbon dioxide less effectively than native grasses. Therefore, these incentives are helping to hasten global warming.

The argument requires the assumption that

Does the position of a car driver’s seat have a significant impact on driving safety? It probably does. Driving position affects both comfort and the ability to see the road clearly. A driver who is uncomfortable eventually becomes fatigued, which makes it difficult to concentrate on the road. Likewise, the better the visibility from the driver’s seat, the more aware the driver can be of road conditions and other vehicles.

Which one of the following most accurately describes the role played in the argument by the claim that driving position affects both comfort and the ability to see the road clearly?

Physician: There were approximately 83,400 trampoline-related injuries last year. This suggests that trampolines are quite dangerous and should therefore be used only under professional supervision.

Trampoline enthusiast: I disagree. In the past ten years sales of home trampolines have increased much more than trampoline-related injuries have: 260 percent in sales compared with 154 percent in injuries. Every exercise activity carries risks, even when carried out under professional supervision.

The dialogue provides the most support for the claim that the physician and the trampoline enthusiast disagree over whether

Interior decorator: All coffeehouses and restaurants are public places. Most well-designed public places feature artwork. But if a public place is uncomfortable it is not well designed, and all comfortable public places have spacious interiors.

If all of the interior decorator’s statements are true, then which one of the following must be true?

In trying to reduce the amount of fat in their diet, on average people have decreased their consumption of red meat by one-half in the last two decades. However, on average those who have reduced their consumption of red meat actually consume substantially more fat than those who have not.

Which one of the following, if true, most helps to resolve the apparent discrepancy described above?