1. Nitrogen gas returns to the atmosphere by the action of
nitrogen fixing bacteria.
denitrifying bacteria.
nitrifying bacteria.
nitrate fertilizers. 15

2. The sequence of energy flow through a food chain is
primary consumers‑ producers‑ higher order consumers.
producers‑ higher order consumers‑ primary consumers.
higher order consumers‑ primary consumers‑ producers.
producers‑ primary consumers‑ higher order consumers.  15

3. highest order consumers. decomposers.
In a terrestrial ecosystem, the trophic level that would contain the largest biomass would be the 
producers.
primary consumers.
secondary consumers.
highest order consumers.
decomposers.  15

4. The study of how living things interact is called:
Ecosystems
Abiotic factors
Ecology
The Energy Pyramid 10

5. The source of energy for almost all life on Earth is:
Fungi
Animals
Water
Sunlight 15

6. In an energy pyramid, the bottom level represents:
Consumers
Producers
Scavengers
Decomposers 15

7. An example of a consumer in a pond ecosystem is:
Water lily
Algae
Reed
Frog 15

8. Which of these food chains is in the correct order?
caterpillar, cattail, frog, water snake
cattail, caterpillar, frog, water snake
water snake, frog, caterpillar, cattail
cattail, frog, caterpillar, water snake 15

9. In an energy pyramid, the lowest level has:
less energy than the top level
less energy than the second level
more energy than the top level
the same amount of energy as the second level 15

10. A food chains shows: one possible pathway for energy
many possible pathways for energy
the amount of energy available to a producer
the amount of energy available to a consumer 15

11. Decomposers are important to ecosystems because they:
are at the highest level of the energy pyramid
change simple compounds into more complex ones
make nutrients available for producers to reuse
convert light energy into sugars through photosynthesis 15

12. Two examples of decomposers are:
fungi and bacteria
algae and marine mammals
carnivores and herbivores
ferns and mosses 15

13. A caterpillar eats a leaf, and a bird eats the caterpillar
A caterpillar eats a leaf, and a bird eats the caterpillar. In this interaction, the bird is a:
Producer
Herbivore
Primary consumer
Secondary consumer 15

14. How is a food web model different from a food chain?
In a web, energy moves from an organism to only one other.
In a web, energy may move to many organisms from one.
In a web, an organism gets energy from one source.
In a web, an organism receives less energy than in a chain. 15

15. An unusually cold winter causes the squirrel population to decrease
An unusually cold winter causes the squirrel population to decrease. This is an example of temperature as a:
Carrying capacity
Limiting factor
Climax community
Pattern in space 15

16. An animal that eats only plants is a:
Primary consumer
Secondary consumer
Tertiary consumer
Primary producer 15

17. A snake that eats an insect-eating frog is a:
Primary consumer
Secondary consumer
Tertiary consumer
Primary producer 15

18. Which of the following is difference between the nitrogen and carbon cycles?
Nitrogen can exist as a solid but carbon cannot.
Carbon is released through decomposition but nitrogen is not.
Carbon is released through respiration but nitrogen is not.
Carbon is cycled through animals but nitrogen is not. 15

19. Which of the following makes the nitrogen cycle unique?
It is the only nutrient cycle without a gas
Nitrogen is always only a liquid
Nitrogen is found in plants, animals and the soil
Nitrogen requires specific bacteria for its cycle 15

20. Which of the following correctly traces the path of a raindrop through the water cycle?
precipitation, run-off, evaporation, condensation
precipitation, condensation, run-off, evaporation
precipitation, evaporation, run-off, condensation
precipitation, evaporation, condensation, run-off 15

21. Which of the following is a way carbon is added to the atmosphere?
Evaporation of water
Forest fires
Photosynthesis
Formation of fossil fuels 15

22. Why are legumes such as peas and alfalfa considered good for soil?
They add valuable humus to the soil when they die and decay.
They absorb water and help control runoff.
Their leaves are able to photosynthesis at a very high rate.
They have nitrogen fixing bacteria in their roots. 15

23. Where is the oxygen we breathe produced?
in the rocks
by decaying organisms
during photosynthesis
as water evaporates 15

24. What is the major factor that limits the number and types of plants that can grow in Utah?
the amount of rainfall we receive
the number of people living Utah
the types of animals found in Utah
the location of Utah on the continent 15

25. Which of the following is a way carbon dioxide can be removed from the air?
building dams
fertilizing crops
mining coal
planting trees 15