As Figure above shows, the distance between particles is much smaller for the solid and liquid states than for the gas state. In the solid state, particles are fixed in place, while particles are more free to move in the liquid and gas states. The particles in the solid and liquid states "stick together," but in the gas state, they move freely about the container. In general, it requires energy to separate individual particles. If we want to make a solid adopt a liquid form, we can add energy in the form of heat, increasing the temperature of the substance. Conversely, if we want to convert a substance from a gas to a liquid or from a liquid to a solid, we remove energy from the system and decrease the temperature. Pressure also plays an important role in changes of state, which will be discussed later on. We will study these difference in greater detail in the chapter States of Matter. John is studying the different states of matter. Today, he has a matter in three states in front of him, state A, state B, and state C. State A is in solid state. State B is in liquid state. And, state C is in gaseous state. He needs to determine the properties of each state. Would state C have less or more distance between particles than state B?
Ans: more

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. Walter and Jesse, two coworkers, are sitting at a hotel bar having a drink together after a long day at a conference when the subject of bad habits comes up. Jesse shares that he has always struggled with biting his nails and no matter what he seems to do he can't kick the habit. Walter's bad habit is that when he plays his weekly baseball game he will use chewing tobacco. He says he doesn't even particularly like the taste anymore, but once he gets to the park he has a craving for it. Which man's chance of having mouth cancer is lower?
Ans: Jesse

If a zone undergoes dramatic changes in temperature with depth, it contains a thermocline. The tropical thermocline is typically deeper than the thermocline at higher latitudes. Polar waters, which receive relatively little solar energy, are not stratified by temperature and generally lack a thermocline because surface water at polar latitudes are nearly as cold as water at greater depths. Below the thermocline, water is very cold, ranging from 1 C to 3 C. Because this deep and cold layer contains the bulk of ocean water, the average temperature of the world ocean is 3.9 C. Keith was measuring the attributes of thermoclines. He selected two locations. One is near Miami, which is in the tropic. The other is near New York, which is in higher latitude. In total, he took four samples, sample A, sample B, sample C, and sample D. From Miami thermocline he took sample A. Then from below Miami thermocline he took sample B. From New York thermocline he took sample C. Finally, from below New York thermocline he took sample D. Which sample would be colder, sample C or sample D?
Ans: sample D

Ecology is the study of ecosystems. An ecosystem consists of all the living and nonliving components of the habitat. Whereas nutrients and certain elements are recycled through ecosystems, energy moves in just one direction. Many interactions among species within an ecosystem are centered around the flow of energy. The formation of ecosystems, from new land to current habitats, is usually based on the pioneer species, and these species are able to live in an area due to the nonliving factors, such as the climate, the soil and the amount of rainfall, of that area. The populations within an ecosystem also determine the stability of the system. Recent tremendous increases in the human population have raised many important ecological issues. Two friends were into natural sciences. Tom was more into Geology, while Rick studied Ecology. Which student read less about living components of the habitat?
Ans: Tom