Answer the following question given this paragraph: The movement of water molecules is not itself regulated by cells, so it is important that cells are exposed to an environment in which the concentration of solutes outside of the cells (in the extracellular fluid) is equal to the concentration of solutes inside the cells (in the cytoplasm). Two solutions that have the same concentration of solutes are said to be isotonic (equal tension). When cells and their extracellular environments are isotonic, the concentration of water molecules is the same outside and inside the cells, and the cells maintain their normal shape (and function). Osmosis occurs when there is an imbalance of solutes outside of a cell versus inside the cell. A solution that has a higher concentration of solutes than another solution is said to be hypertonic, and water molecules tend to diffuse into a hypertonic solution (Figure 3.8). Cells in a hypertonic solution will shrivel as water leaves the cell via osmosis. In contrast, a solution that has a lower concentration of solutes than another solution is said to be hypotonic, and water molecules tend to diffuse out of a hypotonic solution. Cells in a hypotonic solution will take on too much water and swell, with the risk of eventually bursting. A critical aspect of homeostasis in living things is to create an internal environment in which all of the body's cells are in an isotonic solution. Various organ systems, particularly the kidneys, work to maintain this homeostasis. Q: What happens to cells in a hypertonic solution as water leaves the cell via osmosis? Choices: - get larger - evaporation - self destruction - shrinkage A:
shrinkage
(Question)
Answer the following question given this paragraph: The Table below compares the specific heat of four different substances. Metals such as iron have low specific heat. It doesn't take much energy to raise their temperature. That's why a metal spoon heats up quickly when placed in a cup of hot coffee. Sand also has a relatively low specific heat. Water, on the other hand, has a very high specific heat. It takes a lot more energy to increase the temperature of water than sand. This explains why the sand on a beach gets hot while the water stays cool. Differences in the specific heat of water and land even affect climate. To learn how, watch the video at this URL: http://www. youtube. com/watch?v=dkBStF2Rnu4. Q: Why does a metal spoon heat up quickly when placed in a hot drink? Choices: - insulation - high specific heat - convection - low specific heat A:
(Answer)
low specific heat
Ques: Answer the following question given this paragraph: Freezing is the process in which a liquid changes to a solid. It occurs when a liquid cools to a point at which its particles no longer have enough energy to overcome the force of attraction between them. Q: What is the process in which a liquid changes to a solid? Choices: - condensation - boiling - melting - freezing A:
Ans: freezing
(Q).
Answer the following question given this paragraph: Typically, a series of several mutations that constitutively activate oncogenes and inactivate tumor suppressor genes is required to transform a normal cell into a cancer cell ( Figure below ). Cells have developed a number of control mechanisms to overcome mutations in proto-oncogenes. Therefore, a cell needs multiple mutations to transform into a cancerous cell. A mutation in one proto-oncogene would not cause cancer, as the effects of the mutation would be masked by the normal control of the cell cycle and the actions of tumor suppressor genes. Similarly, a mutation in one tumor suppressor gene would not cause cancer either, due to the presence of many "backup" genes that duplicate its functions. It is only when enough proto-oncogenes have mutated into oncogenes and enough tumor suppressor genes have been deactivated that the cancerous transformation can begin. Signals for cell growth overwhelm the signals for growth regulation, and the cell quickly spirals out of control. Often, because many of these genes regulate the processes that prevent most damage to the genes themselves, DNA damage accumulates as one ages. Q: What does a cell need to transform into a cancerous cell? Choices: - microbes - parasites - adaptations - mutations A:
(A).
mutations
Ques:Answer the following question given this paragraph: Most protists are so small that they can be seen only with a microscope. Protists are mostly unicellular (one-celled) eukaryotes. A few protists are multicellular (many-celled) and surprisingly large. For example, kelp is a multicellular protist that can grow to be over 100-meters long ( Figure below ). Multicellular protists, however, do not show cellular specialization or differentiation into tissues. That means their cells all look the same and, for the most part, function the same. On the other hand, your cells often are much different from each other and have special jobs. Q: What type of eukaryotes are protists normally? Choices: - multicellular - photosynthetic - immature - unicellular A:

Ans:unicellular
Ques: Answer the following question given this paragraph: Many people think that any idea that is completely accepted in science is a law. But that is not true. In science, a law is something that always applies under the same conditions. A law explains a fairly simple phenomenon. A theory is much more complex: it tells you why something happens. A law only tells you that it happens. For example, if you hold something above the ground and let go, it will fall. This phenomenon is recognized by the law of gravity ( Figure below ). Some people say that evolution is "just a theory. " But for a complex explanation like evolution, theory is the right word. Q: In science, what do you call something that always applies under the same conditions? Choices: - theory - hypothesis - scientific method - scientific law A:
Ans:
scientific law