Q16: Economist: Tropicorp, which constantly seeks profitable investment opportunities, has been buying and clearing sections of tropical forest for cattle ranching, although pastures newly created there become useless for grazing after just a few years. The company has not gone into rubber tapping, even though greater profits can be made from rubber tapping, which leaves the forest intact. Thus, some environmentalists conclude that Tropicorp has not acted wholly out of economic self-interest. However, these environmentalists are probably wrong. The initial investment required for a successful rubber-tapping operation is larger than that needed for a cattle ranch. Furthermore, there is a shortage of workers employable in rubber-tapping operations, and finally, taxes are higher on profits from rubber tapping than on profits from cattle ranching.
In the economist’s argument, the two boldfaced portions play which of the following roles?
- The first supports the conclusion of the economist’s argument; the second calls that conclusion into question.
- The first states the conclusion of the economist’s argument; the second supports that conclusion.
- The first supports the environmentalists’ conclusion; the second states that conclusion.
- The first states the environmentalists’ conclusion; the second states the conclusion of the economist’s argument.
- Each supports the conclusion of the economist’s argument.
请问第二个黑体部分是什么意思啊？谁能帮我翻译一下？谢谢！ | 
