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: Would sample A1 have less or more isotopes than sample A?
Ans: less

I have a new situation: Helen got lots of different fruit as a gift from a friend that owned an orchard. She received apples, pears, apricots, peaches, plums, quince, among others. She decided to candy apples, apricots, and pears, and to keep the others fresh for as long as possible. But I can use this background: Candied fruit, also known as crystallized fruit or glace fruit, has existed since the 14th century. Whole fruit, smaller pieces of fruit, or pieces of peel, are placed in heated sugar syrup, which absorbs the moisture from within the fruit and eventually preserves it. Depending on size and type of fruit, this process of preservation can take from several days to several months.[1] This process allows the fruit to retain its quality for a year.[2] The continual process of drenching the fruit in syrup causes the fruit to become saturated with sugar, preventing the growth of spoilage microorganisms due to the unfavourable osmotic pressure this creates.[3] What is an answer for this question: Which fruit lasted longer, apricots or quince?
Ans: apricots

I have a new situation: John was studying the history of dinosaurs. He found that dinosaurs were flourishing before 66 million years ago. He labeled it as era A. Then he found that there was a mass extinction around 66 million years ago. He labeled that time period as era B. John found it interesting that many species have evolved in the course of history. But I can use this background: Species go extinct constantly as environments change, as organisms compete for environmental niches, and as genetic mutation leads to the rise of new species from older ones. Occasionally biodiversity on Earth takes a hit in the form of a mass extinction in which the extinction rate is much higher than usual. A large extinction-event often represents an accumulation of smaller extinction- events that take place in a relatively brief period of time.The first known mass extinction in earth's history was the Great Oxygenation Event 2.4 billion years ago. That event led to the loss of most of the planet's obligate anaerobes. Researchers have identified five major extinction events in earth's history since: What is an answer for this question: Which era would more likely be shorter, era A or era B?
Ans: era B

I have a new situation: David was visiting the natural history museum. He noticed two charts that showed the climatic conditions of the earth in two time periods, time A and time B. Time A showed earth's overall climate in the sixteenth century when there were less greenhouse gases in the atmosphere. And time B showed earth's overall climate in the present century with more greenhouse gases in the atmosphere. David found some interesting differences between these two charts. But I can use this background: Greenhouse Effect: The solar energy reaching the surface of the Earth is concentrated in short wavelengths, which can easily penetrate the greenhouse gases, such as carbon dioxide and methane. The Earth, however, is cooler than the sun and it radiates its heat in the form of energy in the far infrared range. These longer wavelengths are partially absorbed by the greenhouse gases and some of the solar heat is returned to Earth. At a certain temperature these processes are in equilibrium and the surface temperature of the Earth is stable. However, if more greenhouse gases are put in the atmosphere the amount of trapped terrestrial radiation increases, leading to an increase in global temperature. What is an answer for this question: Would global temperature in time B be higher or lower than time A's temperature?
Ans: higher