Problem: Given the background: Because of human activities, there is more carbon dioxide in the atmosphere today than in the past hundreds of thousands of years. Burning fossil fuels and has released great quantities of carbon dioxide into the atmosphere. Cutting forests and clearing land has also increased carbon dioxide into the atmosphere because these activities reduce the number of autotrophic organisms that use up carbon dioxide in photosynthesis. In addition, clearing often involves burning, which releases carbon dioxide that was previously stored in autotrophs. and the situation: John has been hearing about climate change for last couple of years. He wants to understand the science behind climate change. For that, he picked up two eras in earth's history, era A and era B. Era A was hundred thousand years ago, and era B is in the present day. He now wants to compare these to eras to understand the change in climate better. Answer the following question: Would era B have more or less carbon dioxide in the air than era A?

A: more

Problem: Given the background: Saturated hydrocarbons are given the general name of alkanes . The name of specific alkanes always ends in - ane . The first part of the name indicates how many carbon atoms each molecule of the alkane has. The smallest alkane is methane. It has just one carbon atom. The next largest is ethane, with two carbon atoms. The chemical formulas and properties of methane, ethane, and several other alkanes are listed in Table below . The boiling and melting points of alkanes are determined mainly by the number of carbon atoms they have. Alkanes with more carbon atoms generally have higher boiling and melting points. and the situation: Vic and Joe studied chemistry in school. Joe studied alkanes, while his friend Vic studied other acyclic hydrocarbons. Answer the following question: Which friend studied less about methane gas?

A: Joe

Problem: Given the background: Human beings invented agriculture about 10,000 years ago. This provided a bigger, more dependable food supply. It also allowed people to settle down in villages and cities for the first time. Birth rates went up because there was more food and settled life had other advantages. Death rates also rose because of crowded living conditions and diseases that spread from domestic animals. Because the higher birth rates were matched by higher death rates, the human population continued to grow very slowly. and the situation: David was studying human history. He selected two specific eras of human history, era A and era B. Era A was before humans had invented agriculture. And, era B was after the invention of agriculture. He noticed that human societies had changed dramatically after the invention of agriculture. Answer the following question: In which era food supply was more dependable, era A or era B?

A: era B

Problem: Given the 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. and the situation: 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. Answer the following question: Which team had fewer people that experienced muscle weakness?

A:
Team Y