Answer the following question given this paragraph: Radiotherapy is effective against cancer because cancer cells reproduce rapidly and, consequently, are more sensitive to radiation. The central problem in radiotherapy is to make the dose for cancer cells as high as possible while limiting the dose for normal cells. The ratio of abnormal cells killed to normal cells killed is called the therapeutic ratio, and all radiotherapy techniques are designed to enhance this ratio. Radiation can be concentrated in cancerous tissue by a number of techniques. One of the most prevalent techniques for well-defined tumors is a geometric technique shown in Figure 32.13. A narrow beam of radiation is passed through the patient from a variety of directions with a common crossing point in the tumor. This concentrates the dose in the tumor while spreading it out over a large volume of normal tissue. The external radiation can be x-rays, 60 Co rays, or ionizing-particle beams produced by accelerators. Accelerator-produced beams of neutrons, -mesons , and heavy ions such as nitrogen nuclei have been employed, and these can be quite effective. These particles have larger QFs or RBEs and sometimes can be better localized, producing a greater therapeutic ratio. But accelerator radiotherapy is much more expensive and less frequently employed than other forms. Q: Radiotherapy is effective against cancer because cancer cells reproduce rapidly and, consequently, are more sensitive to this? Choices: - UV light - separation - destruction - radiation A:
radiation
(Question)
Answer the following question given this paragraph: Bacterial infections of urinary organs, especially the urinary bladder, are common. They are called urinary tract infections. Generally, they can be cured with antibiotic drugs. However, if they aren't treated, they can lead to more serious infections and damage to the kidneys. Q: Antibiotic drugs are usually effective in treating what kind of infections? Choices: - viral - lethal - biological - bacterial A:
(Answer)
bacterial
Ques: Answer the following question given this paragraph: Cyanide inhibits cytochrome c oxidase, a component of the electron transport chain. If cyanide poisoning occurs, would you expect the pH of the intermembrane space to increase or decrease? What effect would cyanide have on ATP synthesis?. Q: Which component of the electron transport chain does cyanide inhibit? Choices: - succinate dehydrogenase - adenosine diphosphate - mitochondrial matrix - cytochrome c oxidase A:
Ans: cytochrome c oxidase
(Q).
Answer the following question given this paragraph: sweating. These vessels become smaller when it is cold outside and larger when it is hot (so more fluid flows, and more energy is transferred). The body also loses a significant fraction of its heat through the breathing process. While convection is usually more complicated than conduction, we can describe convection and do some straightforward, realistic calculations of its effects. Natural convection is driven by buoyant forces: hot air rises because density decreases as temperature increases. The house in Figure 14.17 is kept warm in this manner, as is the pot of water on the stove in Figure 14.18. Ocean currents and large-scale atmospheric circulation transfer energy from one part of the globe to another. Both are examples of natural convection. Q: Natural convection is driven by what forces? Choices: - magnetic - thermal - gravitational - buoyant A:
(A).
buoyant
Ques:Answer the following question given this paragraph: for the period of a simple pendulum. This result is interesting because of its simplicity. The only things that affect the period of a simple pendulum are its length and the acceleration due to gravity. The period is completely independent of other factors, such as mass. As with simple harmonic oscillators, the period T for a pendulum is nearly independent of amplitude, especially if is less than about. Q: The only things that affect the period of a simple pendulum are its length and the acceleration due to gravity. the period is completely independent of other factors, such as this? Choices: - size - rate - speed - mass A:

Ans:mass
Question: Answer the following question given this paragraph: Ice is an example of solid matter. A solid is matter that has a fixed volume and a fixed shape. Figure below shows examples of matter that are usually solids under Earth conditions. In the figure, salt and cellulose are examples of crystalline solids. The particles of crystalline solids are arranged in a regular repeating pattern. The steaks and candle wax are examples of amorphous ("shapeless") solids. Their particles have no definite pattern. Q: What is the name for a matter that has a fixed volume and a fixed shape? Choices: - gas - stable - liquid - solid A:
Answer:
solid