Question 2

TKS plants are developed that produce more rubber than such plants were able to produce at the time the passage was written.

For TKS to become a viable source of rubber, it is essential that TKS plants are bioengineered to produce higher yields of rubber than the current output. This innovation would allow the rubber industry to reduce its dependency on synthetic rubber, which is affected by oil prices.

A) TKS is determined to be free of allergenic proteins.

While being free of allergenic proteins is beneficial for TKS, as mentioned in the extract regarding guayule, it does not directly relate to the viability of TKS as a rubber source. The focus of the passage is on the production yield and the impact of RNA interference on rubber extraction, not on allergenic properties.

B) The price of the oil from which synthetic rubber is made increases significantly from the time the passage was written.

An increase in oil prices would not enhance the viability of TKS as a rubber source. Instead, the passage argues that finding alternative sources, like TKS, with higher rubber yields is crucial for reducing the industry's dependence on oil prices. Thus, this option does not align with the passage's core argument.

C) It is confirmed that rubber from TKS has a more regular structure than that of synthetic rubber.

Confirmation of a more regular structure in TKS rubber compared to synthetic rubber may be relevant for quality considerations but does not address the necessary condition for TKS to be viable. The extract emphasizes the need for increased production yields as the primary focus.

D) TKS plants are developed that produce more rubber than such plants were able to produce at the time the passage was written.

This option is directly supported by the extract, which indicates that higher rubber yield from TKS plants, combined with the RNA interference technique, is essential for making TKS a competitive and viable source of rubber. The passage clearly highlights this aspect as a key to overcoming current production limitations.

E) Land that has been used for growing trees traditionally used for rubber can be developed to be suitable for planting and harvesting TKS at least twice a year.

While this option may discuss the potential for land use, it does not directly address the necessary condition mentioned in the extract regarding TKS's rubber yield. The passage's focus is specifically on enhancing the rubber production of TKS plants themselves rather than land suitability.

Conclusion

The viability of TKS as a rubber source hinges on the development of plants that yield more rubber than previously possible, as outlined in the passage. Options A, B, C, and E fail to address this critical requirement, making D the only correct choice that aligns with the extract's message about enhancing rubber production through bioengineering and RNA interference.