Problem: Given the question: I have a new situation: Two smoker friends found out more about cancer. Bill got scared and started making healthy lifestyle choices, while Dan carried on with his life as if nothing happened. But I can use this background: Making these healthy lifestyle choices can also help prevent some types of cancer. In addition, you can lower the risk of cancer by avoiding carcinogens , which are substances that cause cancer. For example, you can reduce your risk of lung cancer by not smoking. You can reduce your risk of skin cancer by using sunscreen. How to choose a sunscreen that offers the most protection is explained below ( Figure below ). Some people think that tanning beds are a safe way to get a tan. This is a myth. Tanning beds expose the skin to UV radiation. Any exposure to UV radiation increases the risk of skin cancer. It doesn't matter whether the radiation comes from tanning lamps or the sun. What is an answer for this question: Which friend decided to avoid UV lamps?
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The answer is:
Bill

Problem: Given the question: I have a new situation: A group of researches studied the green house gas emissions and their effects on Earth and people during the eighties compared to the twenties. The eighties produced way more green house gasses than the twenties did. But I can use this background: Current Situation : Currently the heating effect of extra greenhouse gases (since the start of the industrial revolution) is equal to about . Thus the recent period has recorded parallel increases in concentration of carbon dioxide and average global temperature. As more greenhouse gases are put into the atmosphere the temperature will increase further. There are certain effects of a warmer Earth (discussed more in optional section), which could accelerate the process, even if no more greenhouse gases are put into the atmosphere (an unlikely prospect for the foreseeable future). What is an answer for this question: During which decade did Earth experience a decreased average global temperature?
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The answer is:
twenties

Problem: Given the question: I have a new situation: David was working in his chemistry lab. He selected two isotopes, sample A and sample B. Sample A had longer half-life, but sample B had shorter half-life. After some time he checked sample A when its one half-life had passed. He noted it as sample A1. Then he came back to see it again when two half-lives had passed. He noted it as sample A2. But I can use this background: Each radioactive isotope has a characteristic decay time periodthe half-lifethat is determined by the amount of time needed for half of a sample to decay. This is an exponential decay process that steadily decreases the proportion of the remaining isotope by 50% every half-life. Hence after two half-lives have passed only 25% of the isotope is present, and so forth. What is an answer for this question: Which sample would have less isotopes, sample A1 or sample A2?
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The answer is:
sample A2