*Question*
Q: Why do comet tails always point away from the sun instead of trailing behind the comet? Read this paragraph and choose the correct option from the provided answers: Figure 29.17 shows a comet with two prominent tails. What most people do not know about the tails is that they always point away from the Sun rather than trailing behind the comet (like the tail of Bo Peep's sheep). Comet tails are composed of gases and dust evaporated from the body of the comet and ionized gas. The dust particles recoil away from the Sun when photons scatter from them. Evidently, photons carry momentum in the direction of their motion (away from the Sun), and some of this momentum is transferred to dust particles in collisions. Gas atoms and molecules in the blue tail are most affected by other particles of radiation, such as protons and electrons emanating from the Sun, rather than by the momentum of photons. Choices: - dust particles attract - dust particles evaporate - dust particles liquify - dust particles recoil A:
**Answer**
dust particles recoil

*Question*
Q: What is the term for the force exerted by circulating blood on the walls of blood vessels? Read this paragraph and choose the correct option from the provided answers: The force exerted by circulating blood on the walls of blood vessels is called blood pressure . Blood pressure is highest in arteries and lowest in veins. When you have your blood pressure checked, it is the blood pressure in arteries that is measured. High blood pressure, or hypertension , is a serious health risk but can often be controlled with lifestyle changes or medication. You can learn more about hypertension by watching the animation at this link: http://www. healthcentral. com/high-blood-pressure/introduction-47-115. html . Choices: - circulation pressure - heart pressure - blood energy - blood pressure A:
**Answer**
blood pressure

*Question*
Q: What device uses electromagnetic induction to change the voltage of electric current? Read this paragraph and choose the correct option from the provided answers: An electric generator is a device that changes kinetic energy to electrical energy through electromagnetic induction. An electric transformer is a device that uses electromagnetic induction to change the voltage of electric current. Choices: - electric combustion - electric conductor - convection device - electric transformer A:
**Answer**
electric transformer

*Question*
Q: Tidal volume, expiratory reserve volume, inspiratory reserve volume, and residual volume are all types of what kind of measurement? Read this paragraph and choose the correct option from the provided answers: 39.2 Gas Exchange across Respiratory Surfaces The lungs can hold a large volume of air, but they are not usually filled to maximal capacity. Lung volume measurements include tidal volume, expiratory reserve volume, inspiratory reserve volume, and residual volume. The sum of these equals the total lung capacity. Gas movement into or out of the lungs is dependent on the pressure of the gas. Air is a mixture of gases; therefore, the partial pressure of each gas can be calculated to determine how the gas will flow in the lung. The difference between the partial pressure of the gas in the air drives oxygen into the tissues and carbon dioxide out of the body. Choices: - respiratory volume - emitted volume - breathing volume - lung volume A:
**Answer**
lung volume