Q: 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:
A: radiation

Q: Answer the following question given this paragraph: Light microscopes continued to improve and are still used today. However, to see extremely small objects, a different type of microscope, such as an electron microscope, must be used. Q: What type of microscope is used to see extremely small objects? Choices: - optical microscope - X-ray microscope - ultrasonic microscope - electron microscope A:
A: electron microscope

Q: Answer the following question given this paragraph: T F = 9 T C + 32 5 5 T C = T F 32 9 T K = T C + 273.15 T C = T K 273.15 Systems are in thermal equilibrium when they have the same temperature. Thermal equilibrium occurs when two bodies are in contact with each other and can freely exchange energy. The zeroth law of thermodynamics states that when two systems, A and B, are in thermal equilibrium with each other, and B is in thermal equilibrium with a third system, C, then A is also in thermal equilibrium with C. 13.2 Thermal Expansion of Solids and Liquids Thermal expansion is the increase, or decrease, of the size (length, area, or volume) of a body due to a change in temperature. Thermal expansion is large for gases, and relatively small, but not negligible, for liquids and solids. Linear thermal expansion is. Q: Systems are in thermal equilibrium when they have the same of what measurement? Choices: - oxygen - density - mass - temperature A:
A: temperature

Q: Answer the following question given this paragraph: Q: In human females, the mammary glands are associated with, but not part of, what organ system that is used to create new humans? Choices: - immune - digestive - endocrine - reproductive A:
A: reproductive