3 minute read
Quiz
by AudioLearn
QUIZ
1. Which process least affects nitrogen fixation on earth in modern times?
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a. Cyanobacteria b. Symbiotic nitrogen-fixers c. Fossil fuel burning d. Lightning strikes
Answer: d. Each of these is a major way that nitrogen fixation occurs; however, lightning strikes play a minor role in this process.
2. What molecule gets made by nitrogen-fixing bacteria?
a. Nitrate b. Nitrite c. Ammonium d. N2
Answer: c. Nitrogen-fixing bacteria get N2 from the atmosphere and make ammonium out of it in the process.
3. Which nitrogen cycle process contributes to greenhouse gases?
a. Denitrification b. Nitrogen fixation c. Nitrogen mineralization d. Nitrification
Answer: a. Denitrification takes the NO3 and turns it ultimately back into N2 gas. This process has intermediaries such as N2O gas, which is a greenhouse gas that contributes to global warming. It ultimately means that all of the burning of fossil fuels and the use of nitrogencontaining fertilizer is contributing to the N2O getting into the atmosphere.
4. Which form of nitrogen is what most contributes to smog?
a. N2 b. b. NH4 c. N2O d. NO
Answer: It’s the NO gas that contributes to smog and the N2O gas that contributes to greenhouse gases. Ultimately, it gets transferred into N2 gas but these intermediaries have led to things like acid rain, smog, and greenhouse gases that have been a direct consequence of using synthetic nitrogen fertilizers.
5. What is the most common ecosystem on earth?
a. Ocean b. Freshwater c. Rain forest d. Desert
Answer: a. The ocean ecosystem is the largest ecosystem, primarily because the oceans comprise about 75 percent of the surface of the earth.
6. In an ecosystem, what does not get recycled as part of the metabolic processes in animals and plants?
a. Nitrogen b. Carbon c. Energy d. Phosphorus
Answer: c. All of the major atoms in the bodies of plants, animals, bacteria, and other species get recycled over and over again; however, energy goes in one direction and gets lost, requiring continual input by the sun in order to have a steady supply of energy.
7. What is not a feature of ecosystems?
a. They are resilient against disturbances b. They are static c. They are resistant to disturbances d. They are biodiverse
Answer: b. Each of these is a feature of ecosystems except that ecosystems are dynamic and are not static. The would fall apart if they are not dynamic.
8. What is the main thing that happens when a population is urn-shaped with a greater population of post-reproductive organisms and few reproductive organisms?
a. The population grows exponentially. b. The population grows at a steady state (or basically stays the same). c. The population declines. d. The population ultimately becomes extinct.
Answer: c. In this type of population, the population declines but does not necessarily become extinct because there are fewer productive organisms.
9. What is least likely to contain the biosphere of the earth?
a. Deep space b. Deep oceans c. Deep within rocks d. Deep into hot springs
Answer: a. Life has naturally been found in each of these areas, making them part of the biosphere, except for the deep space environment, which can allow the survival of bacterial organisms although these have been artificially introduced into the deep space environment by astronauts and aren’t found there naturally.
10. What is an example of an internal climate forcing?
a. Emission of greenhouse gases b. Volcanic eruptions c. Changes in the solar output d. Thermohaline circulation
Answer: d. Each of these is an example of external climate forcing with the exception of thermohaline circulation, which involves a forcing change that takes place within the climate itself rather than externally.
