*Question*
Answer the following question given this paragraph: The hemisphere that is tilted away from the Sun is cooler because it receives less direct rays. As Earth orbits the Sun, the Northern Hemisphere goes from winter to spring, then summer and fall. The Southern Hemisphere does the opposite from summer to fall to winter to spring. When it is winter in the Northern hemisphere, it is summer in the Southern hemisphere, and vice versa. Q: The hemisphere that is tilted away from the sun is cooler because it receives less what? Choices: - direct electrons - x-rays - pollution - direct rays A:
**Answer**
direct rays

*Question*
Answer the following question given this paragraph: Fuels According to the law of conservation of energy, energy can never actually be "consumed"; it can only be changed from one form to another. What is consumed on a huge scale, however, are resources that can be readily converted to a form of energy that is useful for doing work. As you will see in Chapter 18 "Chemical Thermodynamics", energy that is not used to perform work is either stored as potential energy for future use or transferred to the surroundings as heat. A major reason for the huge consumption of energy by our society is the low efficiencyof most machines in transforming stored energy into work. Efficiency can be defined as the ratio of useful work accomplished to energy expended. Automobiles, for example, are only about 20% efficient in converting the energy stored in gasoline to mechanical work; the rest of the energy is released as heat, either emitted in the exhaust or produced by friction in bearings and tires. The production of electricity by coal- or oilpowered steam turbines is significantly more efficient (Figure 5.17 "Electricity from Coal"): about 38% of the energy released from combustion is converted to electricity. In comparison, modern nuclear power plants can be more than 50% efficient. Figure 5.17 Electricity from Coal. Q: Fuels according to the law of what, can never actually be "consumed"; it can only be changed from one form to another? Choices: - use of energy - expansion of energy - difference of energy - conservation of energy A:
**Answer**
conservation of energy

*Question*
Answer the following question given this paragraph: Types of friction include static friction, sliding friction, rolling friction, and fluid friction. Fluid friction with air is called air resistance. Q: What is fluid friction with air called? Choices: - buoyancy - wind resistance - gravity - air resistance A:
**Answer**
air resistance

*Question*
Answer the following question given this paragraph: Q: What property makes bone marrow cells ideal for gene therapy? Choices: - behavior reproduction - irreversible reproduction - Matching - lifelong reproduction A:
**Answer**
lifelong reproduction