USABO Open Exam 2007 Questions and Verified Answers | Passed | A+

The production of the genetically engineered "golden rice" could be important to people of developing nations, especially in South-East Asia, because: A. people are more likely to consume yellow grains than white. B. golden rice is less expensive to grow and harvest than white rice. C. golden rice has been engineered to be resistant to most commercially available herbicides. D. golden rice has been engineered to contain higher concentrations of β-carotene than white rice. E. golden rice has been engineered to produce biodegradable plastics. : D. golden rice has been engineered to contain higher concentrations of β-carotene than white rice. A large population of laboratory rats was allowed to breed randomly for a number of generations. In this population, agouti fur is encoded by the A allele and is dominant to the black fur trait encoded by the a allele. At the beginning of the breeding cycles, 49% of the 2 rats had black fur. At the end of the breeding cycles, this percentage was the same. The rest of the animals had agouti fur. The heterozygotes with agouti fur were indistinguishable from homozygotes with agouti fur. What percentage of this population is probably heterozygous for the fur color trait assuming the rats are following Hardy-Weinberg population genetics? A. 7% B. 30% C. 42% D. 49% E. 70% : C. 42% An individual suffers brain damage that results in respiratory failure. Which region of the brain was most likely damaged?