Environmental Science Quiz

Nitrogen fixation is the process that converts atmospheric nitrogen into forms that can be used by plants. This process is essential because plants cannot directly use atmospheric nitrogen. Nitrogen fixation is carried out by certain bacteria, which convert nitrogen gas into ammonia or other nitrogen compounds that can be absorbed by plants. This allows plants to obtain the necessary nitrogen for their growth and development.

Clearing of tropical forests poses the greatest threat to populations of migratory North American songbirds. This is because these birds rely on these forests as their breeding grounds and stopover sites during migration. When the forests are cleared, their habitat is destroyed, leading to a loss of nesting sites, food sources, and protection from predators. This disruption in their habitat can result in a decline in their population numbers and even extinction in some cases.

Global warming is primarily caused by an increase in greenhouse gases, which leads to rising temperatures on Earth. As temperatures rise, it is more likely that photosynthesis in vegetation will increase rather than decrease. This is because higher temperatures can enhance the efficiency of photosynthesis, allowing plants to produce more energy. Therefore, the decreased rate of photosynthesis in vegetation is the least likely effect of global warming.

Sand has the greatest permeability among the given substances. Permeability refers to the ability of a material to allow fluids or gases to pass through it. Sand has larger particles compared to clay, silt, and loam, which allows for greater pore spaces and better drainage. This means that water or other substances can easily flow through sand, making it more permeable than the other options.

The correct answer is descending dry air currents. Deserts are typically found at approximately 30 degrees latitude because at these locations, the air is sinking and becoming drier. As the air descends, it warms up and loses moisture, resulting in arid conditions and the formation of deserts. This process is known as subsidence, and it creates a stable atmospheric environment that inhibits the formation of clouds and precipitation.

The presence of heavy metals in municipal sewage sludge would be the strongest indicator that it is unfit for use as fertilizer. Heavy metals are toxic and can contaminate crops, posing risks to human health and the environment. Therefore, if heavy metals are present in the sludge, it would be unsafe to use it as fertilizer.

Exotic species often experience a rapid increase in population when introduced to a new environment due to the availability of a large, underused food source. This means that they have access to an abundance of resources, allowing them to reproduce and thrive. Additionally, the lack of natural predators in the new environment further contributes to their population growth, as they face fewer threats and can reproduce without significant predation pressure. Therefore, the correct answer is II and III only.

Chlorofluorocarbon (CFC) has the greatest heat-trapping ability per molecule compared to the other greenhouse gases listed. This is because CFCs have a high global warming potential, meaning they have a strong ability to absorb and trap heat in the atmosphere. Additionally, CFCs have a long atmospheric lifetime, allowing them to persist in the atmosphere for a long time and continue contributing to global warming. Methane, carbon dioxide, nitrous oxide, and carbon monoxide also contribute to global warming, but their heat-trapping abilities per molecule are lower than that of CFCs.

The country's current population is 100 million, and the annual growth rate is 3.5%. This means that every year, the population will increase by 3.5% of its current value. To calculate the population in 40 years, we need to multiply the current population by (1 + growth rate) raised to the power of the number of years. In this case, it would be 100 million * (1 + 0.035) ^ 40, which equals approximately 400 million.

Coal-burning power plants release radioactive as well as toxic materials such as lead and arsenic under normal operating conditions. Burning coal produces ash and emissions that contain these harmful substances, which can be released into the air and water. This pollution poses significant health risks to both humans and the environment.