Problem: 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 A2?

A: more

Problem: I have a new situation: Mark works as a scientist for a molecular research institute. Today, he has three samples of molecule in front of him, sample A, sample B, and sample C. Sample A is a straight-chain molecule; sample B is a branched-chain molecule; and sample C is a cyclic molecule. Mark's job is to determine the characteristics of each sample. But I can use this background: A) In a straight-chain molecule, all the carbon atoms are lined up in a row like cars of a train. The carbon atoms form the "backbone" of the molecule. B) In a branched-chain molecule, at least one of the carbon atoms branches off from the backbone. C) In a cyclic molecule, the chain of carbon atoms is joined at the two ends to form a ring. Each ring usually contains just five or six carbon atoms, but rings can join together to form larger molecules. A cyclic molecule generally has higher boiling and melting points than straight-chain and branched-chain molecules. What is an answer for this question: In which sample the chain of carbon atoms would not form a ring, sample B or sample C?

A: sample B

Problem: I have a new situation: Dan is a geneticist and studied two villages from 2,000 years ago. Village A displayed traces of a large population that grew larger over the years, while village B had a small and declining population and was more isolated geographically. But I can use this background: Declines in population size can result in a loss of genetic diversity, and owing to genetic variation's role in the evolutionary potential of a species, this could in turn result in an observable Allee effect. As a species' population becomes smaller, its gene pool will be reduced in size as well. One possible outcome from this genetic bottleneck is a reduction in fitness of the species through the process of genetic drift, as well as inbreeding depression. This overall fitness decrease of a species is caused by an accumulation of deleterious mutations throughout the population. Genetic variation within a species could range from beneficial to detrimental. Nevertheless, in a smaller sized gene pool, there is a higher chance of a stochastic event in which deleterious alleles become fixed (genetic drift). While evolutionary theory states that expressed deleterious alleles should be purged through natural selection, purging would be most efficient only at eliminating alleles that are highly detrimental or harmful. Mildly deleterious alleles such as those that act later in life would be less likely to be removed by natural selection, and conversely, newly acquired beneficial mutations are more likely to be lost by random chance in smaller genetic pools than larger ones.Although the long-term population persistence of several species with low genetic variation has recently prompted debate on the generality of inbreeding depression, there are various empirical evidences for genetic Allee effects. One such case was observed in the endangered Florida panther (Puma concolor coryi). The Florida panther experienced a genetic bottleneck in the early 1990s where the population was reduced to 25 adult individuals. This reduction in genetic diversity was correlated with defects that include lower sperm quality, abnormal testosterone levels, cowlicks, and kinked tails. In response, a genetic rescue plan was put in motion and several female pumas from Texas were introduced into the Florida population. This action quickly led... What is an answer for this question: Which village didn't have a reduced gene pool?

A: Village A

Problem: I have a new situation: Two ladies sit in a coffee shop. Patty smokes three packs of cigarettes a day, but her good friend Julie, doesn't smoke. They are both 65 years old. They are enjoying a coffee. But I can use this background: Many different chemical substances cause cancer. Dozens of chemicals in tobacco smoke, including nicotine, have been shown to cause cancer ( Figure below ). In fact, tobacco smoke is one of the main sources of chemical carcinogens. Smoking tobacco increases the risk of cancer of the lung, mouth, throat, and bladder. Using smokeless tobacco can also cause cancer. Other chemicals that cause cancer include asbestos, formaldehyde, benzene, cadmium, and nickel. What is an answer for this question: Which lady has a lower risk of getting mouth cancer?

A:
Julie