*A farmer uses triazine herbicide to control pigweed in his…

*A farmer uses triazine herbicide to control pigweed in his field. For the first few years, the triazine works well and almost all the pigweed dies; but after several years, the farmer sees more and more pigweed. Which of these explanations best explains what happened?

You are the owner of Jurassic Park, and you want to set abou…

You are the owner of Jurassic Park, and you want to set about populating your park with extinct animals. The first animal you want to have in your park is a wooly mammoth, and you have a remarkably well-preserved specimen that was frozen in the Arctic ice 20,000 years ago. Design a method for populating your park with many living wooly mammoths.