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Human population growth has led to a reduction in the populations of predators throughout natural ecosystems across the United States. Scientists consider the loss of these predators to have a*
Which human activity would interfere most directly with the production of oxygen in the environment?*
Environmentalists are hoping to protect endangered organisms by calling for a reduction in the use of pesticides, because loss of these organisms would*
Which farming practice causes the least harm to the environment?*
Which action by humans could improve the quality of the air?*
Increased human population growth usually results in*
In 2003, the city of Rochester, New York, began killing weeds with steam. A machine heats water to 280°F then sprays it on the weeds with great pressure. The extreme heat destroys the cellular structure of the plants. What is a possible disadvantage of this method of weed control?*
Which graph best illustrates the change in the human population over the past 2000 years?*
In New York State, cars are inspected to be sure they are not releasing excessive amounts of several gases into the atmosphere. This is done in an effort to*
Certain animal species that are endangered or threatened have been cloned. Closely related species have been used to carry the embryos of the endangered species. This process of increasing the population size of a species in danger of becoming extinct is an example of a*
Car manufacturers have begun to explore the use of biofuels, such as biodiesel, ethanol, and cooking oils made from plant material. The desired outcome of using these biofuels would be*
Base your answers to questions 12 on the information below and on your knowledge of biology.
Decline in the Amphibians
Declines in amphibian species, such as frogs, toads and salamanders, might affect the ways in which ecosystems function. Amphibians prey on many types of small organisms that survive by consuming leaf litter (leaf material on the ground of ecosystems). These small organisms include animals such as earthworms, centipedes, millipedes, pill bugs, and many species of insects. In turn, amphibians are preyed on by fish, herons, chipmunks, turkeys, foxes, coyotes, and other animals.
Human activities often cause a reduction in the size of amphibian populations. As amphibian populations are reduced, the organisms that are preyed on by amphibians increase in number. As the populations of small forest organisms increase, the amount of leaf litter decreases. The decrease in the amount of leaf litter on the forest floor may have negative effects on the forest ecosystem.
Identify one human activity and describe how that activity could directly or indirectly lead to a reduction in amphibian populations. *
Base your answer to question 13-16 on the information and graph below and on your knowledge of biology.
At an observatory in Mauna Loa, Hawaii, scientists have been measuring and collecting data related to changes in the atmosphere since the 1950s. The remote location of the observatory makes it ideal for studying atmospheric conditions that can cause climate change. One specific measurement taken is the amount of atmospheric carbon dioxide. Information for a 7-year period is shown in the graph below.
Analyze the data shown in the graph. In your answer, be sure to:
• state the overall relationship between time and carbon dioxide levels 
• state one possible cause for the overall change in the carbon dioxide levels shown in the graph 
• identify the biological process that might account for the decreases in carbon dioxide levels 
• identify two actions carried out by humans that could lower carbon dioxide levels *
Base your answers to questions 17 on the information below and on your knowledge of biology.
Mosquito Technologies of New York, Inc., has developed a Mosquito Killing System (MKS) to help control the mosquito population and reduce the transmission of West Nile Virus. The MKS works by taking advantage of the natural hunting strategies of mosquitoes, such as heat sensing and carbon dioxide detection. Beneficial insects do not use the same hunting strategies. The MKS unit produces heat and releases carbon dioxide in cycles, mimicking the breathing and body temperatures of humans, pets, and other warm-blooded animals. This attracts the mosquitoes to the device and, once inside, a vacuum pulls them in, where they pass through an electrocution grid, killing them. The mosquito remains are then returned to the environment through the bottom of the unit.
The unit contains a solar-powered photocell that turns the device on at dusk and turns it off at dawn.
State one positive effect the use of this MKS device has on the environment. *
Base your answers to questions 18 on the information below and on your knowledge of biology.
Gray Wolves in the Rocky Mountains
Reintroduction of gray wolves in the northern Rocky Mountains has increased the ecological health of Yellowstone National Park in Wyoming. When all wolves in Yellowstone National Park were killed in 1920, elk soon ate trees and shrubs down to short stubs. Now that wolves are reducing elk numbers, many aspens and willow trees are taller and fuller and birds are returning to the trees to nest. The beaver population has grown from one colony to 12 colonies in 13 years. Spreading these benefits across the Rocky Mountain region would require increasing the present wolf population of 1,770 to 17,000.
In September 2012, wolves lost federal protection in Wyoming. In 2014, Wyoming closed its hunting season after meeting its quota of 26 wolves around Yellowstone and Grand Teton parks. The sizes of traps to catch wolves have been regulated to reduce the chance of trapping endangered species such as lynx and wolverines and the hunting season was shortened. Some ecologists wonder if removing the wolves from federal protection and allowing them to be hunted is a good ecological decision.
Explain how increasing the wolf population caused an increase in birds and beavers. *