Background: Old age begins in the mid-60s and lasts until the end of life. Most people over 65 have retired from work, freeing up their time for hobbies, grandchildren, and other interests. Stamina, strength, reflex time, and the senses all decline during old age, and the number of brain cells decreases as well. The immune system becomes less efficient, increasing the risk of serious illnesses such as cancer and pneumonia. Diseases such as Alzheimer's disease that cause loss of mental function also become more common. Paragraph: Doctors studied two groups of individuals: group O with people over 65, and group S with people under 65 years old. They published the results in a magazine. Given the paragraph above, please answer correctly the following question: Which group had fewer people that have free time for grandchildren?
Ans: group S

Background: The primary role of red blood cells in the circulatory system is to transport oxygen to the tissues. The actual carrier of oxygen molecules is the protein hemoglobin, which binds to the oxygen and moves it throughout the body, releasing it in areas where the concentration of dissolved oxygen is low. A certain mutation in the gene for hemoglobin causes a slight change in the structure of this crucial protein, resulting in a disease called sickle-cell anemia. For people with this mutation, the hemoglobin produced by their red blood cells has a tendency to clump together, distorting the shape of the red blood cells and giving rise to the crescent-shaped cells seen above. By understanding the changes in structure that are the underlying cause of this disease, we have developed various ways to treat and manage this illness. Paragraph: Doctors studied Dan, a normal patient, whit a normal number of red blood cells, and Jim, a patient that had sickle-cell anemia. The differences were remarkable in terms of overall well-being and health. Given the paragraph above, please answer correctly the following question: Which patient had more normal shaped red blood cells, Dan or Jim?
Ans: Dan

Background: Millions of people in the world jog for exercise. For the most part, jogging can be a healthy way to stay fit. However, problems can also develop for those who jog in the heat. Excessive sweating can lead to electrolyte loss that could be life-threatening. Early symptoms of electrolyte deficiency can include nausea, fatugue, and dizziness. If not treated, individuals can experience muscle weakness and increased heart rate (which could lead to a heart attack). Many sports drinks can be consumed to restore electrolytes quickly in the body. Paragraph: Two teams of runners were training for a 10k. Team Y jogged early in the morning when the weather was cool. Team X started their training in the heat so many team members had problems sweating. Given the paragraph above, please answer correctly the following question: Which team had fewer people that experienced muscle weakness?
Ans: Team Y

Background: All of these animal behaviors are important. They help the animals get food for energy, make sure their young survive, or ensure that they, themselves, survive. Behaviors that help animals or their young survive, increase the animals' fitness. Animals with higher fitness have a better chance of passing their genes on to the next generation. If genes control behaviors that increase fitness, the behaviors become more common in the species. This occurs through the process of evolution by natural selection. Paragraph: David is a biologist. He was in the African savanna to study different species. Especially, he was interested in two species, rhinos and impalas. He noticed that in response to constant human encroachment of wildlife habitats, impalas have acquired some behaviors that help them and their young. Rhinos also have acquired some behaviors in response to the same threat. But their behaviors mostly failed them in that aspect. Given the paragraph above, please answer correctly the following question: In which species the behaviors in question would be more common, rhino or impala?
Ans: impala