Answer the following question given this paragraph: human body system that includes all the muscles of the body. Q: Compound light microscopes use lenses to do what? Choices: - stop light - twist light - burn light - focus light A:
focus light
(Question)
Answer the following question given this paragraph: 10.4 | Cancer and the Cell Cycle By the end of this section, you will be able to: Describe how cancer is caused by uncontrolled cell growth Understand how proto-oncogenes are normal cell genes that, when mutated, become oncogenes Describe how tumor suppressors function Explain how mutant tumor suppressors cause cancer Cancer comprises many different diseases caused by a common mechanism: uncontrolled cell growth. Despite the redundancy and overlapping levels of cell cycle control, errors do occur. One of the critical processes monitored by the cell cycle checkpoint surveillance mechanism is the proper replication of DNA during the S phase. Even when all of the cell cycle controls are fully functional, a small percentage of replication errors (mutations) will be passed on to the daughter cells. If changes to the DNA nucleotide sequence occur within a coding portion of a gene and are not corrected, a gene mutation results. All cancers start when a gene mutation gives rise to a faulty protein that plays a key role in cell reproduction. The change in the cell that results from the malformed protein may be minor: perhaps a slight delay in the binding of Cdk to cyclin or an Rb protein that detaches from its target DNA while still phosphorylated. Even minor mistakes, however, may allow subsequent mistakes to occur more readily. Over and over, small uncorrected errors are passed from the parent cell to the daughter cells and amplified as each generation produces more non-functional proteins from uncorrected DNA damage. Eventually, the pace of the cell cycle speeds up as the effectiveness of the control and repair mechanisms decreases. Uncontrolled growth of the mutated cells outpaces the growth of normal cells in the area, and a tumor ("-oma") can result. Q: Uncontrolled cell growth can lead to tumors and what disease? Choices: - vascular disease - cirrhosis - kidney failure - cancer A:
(Answer)
cancer
Ques: Answer the following question given this paragraph: Metal is regularly used in the human body for hip and knee implants. Most implants need to be replaced over time because, among other things, metal does not bond with bone. Researchers are trying to find better metal coatings that would allow metalto-bone bonding. One challenge is to find a coating that has an expansion coefficient similar to that of metal. If the expansion coefficients are too different, the thermal stresses during the manufacturing process lead to cracks at the coating-metal interface. Another example of thermal stress is found in the mouth. Dental fillings can expand differently from tooth enamel. It can give pain when eating ice cream or having a hot drink. Cracks might occur in the filling. Metal fillings (gold, silver, etc. ) are being replaced by composite fillings (porcelain), which have smaller coefficients of expansion, and are closer to those of teeth. Q: What material is regularly used in human hip and knee implants? Choices: - wood - glass - coal - metal A:
Ans: metal
(Q).
Answer the following question given this paragraph: Glia While glia are often thought of as the supporting cast of the nervous system, the number of glial cells in the brain actually outnumbers the number of neurons by a factor of ten. Neurons would be unable to function without the vital roles that are fulfilled by these glial cells. Glia guide developing neurons to their destinations, buffer ions and chemicals that would otherwise harm neurons, and provide myelin sheaths around axons. Scientists have recently discovered that they also play a role in responding to nerve activity and modulating communication between nerve cells. When glia do not function properly, the result can be disastrousmost brain tumors are caused by mutations in glia. Types of Glia There are several different types of glia with different functions, two of which are shown in Figure 35.7. Astrocytes, shown in Figure 35.8a make contact with both capillaries and neurons in the CNS. They provide nutrients and other substances to neurons, regulate the concentrations of ions and chemicals in the extracellular fluid, and provide structural support for synapses. Astrocytes also form the blood-brain barriera structure that blocks entrance of toxic substances into the brain. Astrocytes, in particular, have been shown through calcium imaging experiments to become active in response to nerve activity, transmit calcium waves between astrocytes, and modulate the activity of surrounding synapses. Satellite glia provide nutrients and structural support for neurons in the PNS. Microglia scavenge and degrade dead cells and protect the brain from invading microorganisms. Oligodendrocytes, shown in Figure 35.8b form myelin sheaths around axons in the CNS. One axon can be myelinated by several oligodendrocytes, and one oligodendrocyte can provide myelin for multiple neurons. This is distinctive from the PNS where a single Schwann cell provides myelin for only one axon as the entire Schwann cell surrounds the axon. Radial glia serve as scaffolds for developing neurons as they migrate to their end... Q: Though often regarded as the supporting cast of the nervous system, glial cells in the brain actually outnumber what by a factor of ten? Choices: - blood cells - electrons - muscles - neurons A:
(A).
neurons
Ques:Answer the following question given this paragraph: Earth goes through regular changes in its position relative to the Sun. Its orbit changes slightly. Earth also wobbles on its axis of rotation. The planet also changes its axial tilt , the angle of its axis of rotation. These changes can affect Earth's temperature. Q: What do you call the angle of the earth's axis of rotation? Choices: - dynamic tilt - vertical tilt - horizontal tilt - axial tilt A:

Ans:axial tilt
Answer the following question given this paragraph: Q: This process breaks rocks and other surface materials into much smaller pieces? Choices: - corrosion - leaching - chemical reaction - weathering A:
weathering