1. Part A Answer all questions in this part. [30] Directions (1 - 30): For each statement or question, record on the separate answer sheet the number of the word or expression that, of those given, best completes the statement or answers the question. 1 Which activity is an example of a decomposer recycling organic compounds back into the environment? (1) A tree synthesizes starch from simpler molecules. (2) A bacterial cell performs photosynthesis. (3) A bird digests proteins from its food. (4) A fungus breaks down the body of a dead animal.   1   2   3   4   Hint Half-n-half Clue   2. 2 Itching and other skin problems are signs that a cat or dog may have fleas. Fleas are parasites known for their biting and blood-sucking abilities. When they bite, flea saliva enters the pet’s circulatory system, sometimes causing an allergic response commonly seen as a “hot spot” on the pet’s neck or the base of its tail. These observations are best explained by the fact that (1) flea saliva may stimulate an immune response in cats and dogs (2) fleas are microbes whose bites cause a decreased blood flow (3) flea saliva is a toxic substance that is released when fleas prey on cats and dogs (4) fleas are host organisms whose saliva digests cat and dog fur, leaving “hot spots”   1   2   3   4   Half-n-half Clue   3. 3 A German measles (rubella) epidemic during the years 1963 to 1965 resulted in approximately 30,000 babies being born with birth defects. The specific cause of these birth defects was most likely (1) the development of rubella virus infections in embryos (2) the failure of zygotes infected with rubella to develop (3) mutations in the nerve cells of pregnant females at the time of the rubella epidemic (4) an increase in the amount of time needed for healthy embryonic development   1   2   3   4   Half-n-half Clue   4. 4 Placenta previa is a medical condition that occurs in some pregnant women. Women with this condition are often placed on bed rest, which prohibits them from any strenuous activity that may cause the blood vessels in the placenta to rupture. If not diagnosed, placenta previa can be a very dangerous condition because the placenta is (1) the primary source of oxygen for the mother (2) where the fetus obtains milk from the mother (3) where nutrients and wastes are exchanged (4) the primary source of estrogen and progesterone in the mother   1   2   3   4   Half-n-half Clue   5. 5 Over time, a tree that once had a total mass of 300 g increased in mass to 3000 kg. This increase in mass comes mostly from (1) carbon dioxide that enters through the leaf openings (2) oxygen that enters through the leaf openings (3) soil that all plants need to grow (4) chloroplasts that enter the roots and move to the leaves   1   2   3   4   Half-n-half Clue   6. 6 Recently, a type of genetically modified fish has been approved for sale for human consumption. The modified fish contain a growth hormone gene from a different fish species. As a result, the modified fish grow rapidly and are ready to sell in almost half the time it normally would take. The modified fish are able to produce the new growth hormone because (1) each of their cells contains the new gene to produce growth hormone (2) each gene contains the code to synthesize carbohydrates (3) the altered gene directs the mitochondria to synthesize the hormone (4) the modified body cells are able to reproduce by meiosis   1   2   3   4   Half-n-half Clue   7. 7 Melanoma is a type of skin cancer that can spread to vital organs in the body. Doctors believe that exposure to ultraviolet (UV) radiation from the Sun is a leading cause of melanoma. One practical way governments can help prevent the harmful effects of UV radiation is to (1) require everyone to remain indoors during daylight hours (2) regulate the production and release of gases that damage the ozone shield (3) encourage the building of a greater number of cancer treatment centers (4) prohibit the use of solar panels on homes and businesses   1   2   3   4   Half-n-half Clue   8. 8 Some birds have recently modified their migratory behavior. Instead of flying to warmer climates during the winter months, the birds are remaining in northern areas where they can consume discarded food that is abundant in landfills. As a result of this change in migratory behavior, many insect populations that the birds normally feed on in the warmer climate areas are now increasing. This is an example of human activity (1) interfering with ecological succession (2) increasing competition for infinite resources (3) disrupting the homeostasis of organisms (4) altering the equilibrium of ecosystems   1   2   3   4   Half-n-half Clue   9. 9 New York State charges consumers a fee when purchasing beverages sold in aluminum cans and plastic bottles. This money is returned to purchasers when they return these items for recycling. Programs such as these are an attempt to (1) encourage people to spend more money on their beverages (2) conserve the resources these containers are made from (3) reduce the amount of carbon dioxide produced by deforestation (4) totally eliminate the use of reusable containers   1   2   3   4   Half-n-half Clue   10. 10 Recently, a human trachea (a respiratory organ) was produced by using a patient’s own stem cells. The benefit of using the patient’s own cells to produce a trachea instead of receiving one from a donor is that (1) there will be more enzymes produced to help maintain homeostasis in the trachea (2) there will be an increase in the quantity of antibodies that the patient produces in response to the new trachea (3) there is less of a chance that the patient’s immune system will attack the trachea (4) there will be a greater response to any infectious agent that may enter the body   1   2   3   4   Half-n-half Clue   11. 11 The diagram below represents the organization of structures within an organism. Which term best indicates the structures represented by the circle labeled X? (1) organelles (3) organ systems (2) chromosomes (4) tissues   1   2   3   4   Half-n-half Clue   12. 12 The chart below shows a comparison of the blood sugar levels for two individuals who took part in a scientific study. Scientists have observed that blood sugar levels rose by different amounts in the two individuals even though they were given identical portions of bananas and cookies. These results were obtained because (1) glucose is too large a molecule to be absorbed into the blood, so the researchers were only measuring the amount of glucose already present (2) participant 445 didn’t like bananas, and his body absorbed more of the food that he likes (3) individuals have genetic differences that alter their responses to environmental factors (4) two different foods were used; the scientists should have had only one experimental variable   1   2   3   4   Half-n-half Clue   13. 13 Which row in the chart below correctly matches the human activity with its effect?   1   2   3   4   Half-n-half Clue   14. 14 Potatoes are an example of a crop that can be reproduced asexually. One potato will produce a number of “eyes,” which are sprouts that can grow into new plants. A potato with four eyes can be cut into four pieces, and each piece can be used to produce an individual potato plant. A gardener could produce a small crop of potatoes by planting the eyes from a single potato in her garden. Some of the potatoes grown in this way could be used to obtain eyes for the next season’s crop. One likely disadvantage of growing potatoes cloned in this way, year after year, would be that (1) after a few years, the potatoes would stop producing eyes altogether, so no potatoes could be grown in the garden (2) the potatoes produced each succeeding year would get larger and larger, eventually being too big for use as food (3) the cost for growing your own potatoes in the garden would be greatly reduced (4) a potato plant could become infected with a disease, and it could easily spread to the entire crop, killing all of the plants   1   2   3   4   Half-n-half Clue   15. 15 The back of the Namib Desert darkling beetle, shown in the photograph below, is covered in little bumps that collect water from the air. When it tilts forward, the water runs off its back into its mouth. These specialized structures on the beetle’s back allow it to (1) locate food within the harsh desert environment (2) obtain a substance that is required for survival (3) reproduce asexually if mates are not available in the area (4) increase the chances of survival by producing organic raw materials   1   2   3   4   Half-n-half Clue