Unit 2: Natural resources and ecosystem - Practice Quiz

1 What are natural resources?

2 Which of the following is a renewable resource?

3 Which resource is classified as non-renewable?

4 Which resource provides habitat for many wild plants and animals?

5 Which activity uses the largest share of freshwater in many countries?

6 Which energy resource is obtained from moving air?

7 Which method helps reduce soil erosion on steep slopes?

8 What is a major result of excessive removal of trees?

9 Which practice helps replenish groundwater?

10 Which individual action directly conserves water?

11 Which action helps conserve energy at home?

12 Which of the following is a biotic component of an ecosystem?

13 What is the main role of decomposers in an ecosystem?

14 Which of the following is an aquatic ecosystem?

15 Which ecosystem usually receives very little rainfall?

16 What is the primary source of energy for most ecosystems?

17 In the food chain grass → deer → tiger, which organism is the producer?

18 What does a food web represent?

19 Which organisms usually form the base of an ecological pyramid?

20 What is ecological succession?

21 A village depends on groundwater for drinking and irrigation. Which statement best explains why groundwater is considered a natural resource?

22 Which situation best illustrates that a renewable resource can still become scarce?

23 Which agricultural practice is most effective in reducing soil erosion on a steep slope?

24 A town experiences falling groundwater levels despite receiving normal annual rainfall. Which change would most directly help restore groundwater?

25 A reservoir is receiving large amounts of soil from surrounding hills, reducing its storage capacity. Which remedial measure is most appropriate?

26 Which combination most effectively reduces the environmental problems caused by excessive dependence on fossil fuels?

27 Which individual action would conserve both water and energy in a household?

28 A student wants to reduce the amount of waste sent to a landfill. Which choice follows the waste-management hierarchy most effectively?

29 In an ecosystem, decomposers are essential mainly because they

30 Which example correctly matches an ecosystem component with its role?

31 A pond contains algae, fish, aquatic plants, microbes, water, dissolved salts, and sunlight. Which classification best describes this system?

32 Which feature most clearly distinguishes an artificial ecosystem from a natural ecosystem?

33 If producers in an ecosystem store units of energy, approximately how much energy may be available to primary consumers according to the ten-percent law?

34 Why does energy flow through an ecosystem rather than cycle like nutrients?

35 In the food chain grass grasshopper frog snake, what is the likely immediate effect of a sharp decrease in frogs?

36 Why is a food web generally more stable than a single food chain?

37 Which ecological pyramid is always upright in a normal ecosystem?

38 An ecosystem has one large tree supporting many insects and birds. Which pyramid may have an inverted shape at the producer and primary-consumer levels?

39 Which sequence best represents primary succession on newly exposed bare rock?

40 A grassland is destroyed by fire, but the soil and some seeds remain. The subsequent recovery is an example of

41 A coastal wetland supports fisheries, buffers storm surges, stores carbon, and provides habitat for migratory birds. A valuation study counts fish harvest revenue and avoided storm damage but excludes carbon storage and habitat support. Which conclusion is most defensible?

42 A confined aquifer receives negligible modern recharge, while a forest regrows naturally if annual harvest remains below net growth. Which classification best reflects resource dynamics rather than merely resource identity?

43 A fish population follows logistic growth, . Ignoring age structure and environmental variability, at what population size is the theoretical maximum sustainable yield obtained?

44 An irrigated basin has rising groundwater, increasing soil salinity, and declining crop yields despite adequate rainfall. Which intervention most directly addresses the coupled cause of the degradation?

45 A region must choose an electricity project using life-cycle analysis. Project P has low operating emissions but high construction emissions; Project Q has moderate operating emissions and low construction emissions. What information is essential for a valid climate comparison?

46 Two forest plans remove the same timber volume. Plan I clear-cuts one contiguous block; Plan II removes scattered trees across a larger area while building many access roads. Which statement best explains why Plan II may produce greater ecological damage?

47 A watershed experiences severe peak floods, reduced dry-season streamflow, and heavy sedimentation after conversion of upland forest to compacted cropland. Which restoration package best addresses all three symptoms?

48 A common pasture is degraded because each herder receives the full benefit of adding an animal but shares the resulting grazing cost with all users. Which policy most directly aligns individual incentives with the pasture's carrying capacity?

49 A household can either replace a functioning refrigerator immediately with a highly efficient model or continue using it for several years. Which criterion gives the most defensible conservation decision?

50 In a grassland experiment, decomposers are strongly suppressed while plant photosynthesis and herbivore abundance initially remain unchanged. Which effect is most likely after several growing seasons?

51 An ecosystem has gross primary productivity of . Producers use in respiration, and herbivores consume of plant production. What are the net primary productivity and the plant production entering detrital or storage pathways?

52 A shallow lake shifts from clear water with submerged plants to turbid water dominated by phytoplankton after nutrient enrichment. Nutrient inputs are then reduced slightly, but the turbid state persists. Which concept best explains this response?

53 Compared with an oligotrophic lake of similar depth, a eutrophic lake undergoes strong summer stratification and receives high organic inputs. Which oxygen pattern is most likely before autumn mixing?

54 Producers store as net production. Herbivores ingest , egest , and spend in respiration. What are the herbivores' assimilation efficiency and production efficiency?

55 A contaminant reduces producer respiration without changing gross photosynthesis, but it does not directly affect consumers. Which immediate ecosystem-level change is expected, assuming other losses remain constant?

56 In a rocky-shore food web, sea stars consume mussels, and mussels competitively exclude several other sessile species when abundant. Removing sea stars causes species richness to decline. Which mechanism best explains the result?

57 A pesticide enters a lake at low concentration, is persistent, lipid-soluble, and poorly metabolized. The food web is phytoplankton zooplankton small fish fish-eating birds. Which observation would best demonstrate biomagnification rather than only bioaccumulation?

58 An open-ocean ecosystem has a smaller standing biomass of phytoplankton than of zooplankton at a given instant, yet phytoplankton support the zooplankton population. Which statement resolves this apparent contradiction?

59 A grassland has producer net production of . Transfer efficiencies are from producers to herbivores, from herbivores to primary carnivores, and from primary to secondary carnivores. How much production reaches the secondary carnivores?

60 Two sites are abandoned simultaneously: Site X is exposed bare rock after glacial retreat, while Site Y is an abandoned cultivated field with intact soil and a surviving seed bank. Which comparison is most accurate?