Which of the following can carry out denitrification

31) Which of the following can carry out denitrification to
completion?
A) Rhizobium
B) Nitrobacter
C) Pseudomonas
D) Nostoc
E) Azotobacter
32) Which organism is a nitrogen-fixing symbiont of
legumes?
33) Thiobacillus thiooxidans is found in an environmental
sample. Which of the following should then apply to this
sample?
Version 1 19

D) All of these choices are correct.
Version 1 20

34) Life would not be possible without
35) Using microbes to break down or remove toxic wastes
in water and soil is called
A) decomposition.
B) synergism.
C) mineralization.
D)
bioremediation.
E) recycling.
36) The sediment in a lake, composed of organic debris
and mud, is termed the
37) All of the following pertain to red tides, except
Version 1 21

C) occurs when there are excess nutrients in aquatic
ecosystems.
D) causes massive die-off of fish and invertebrates.
E) All of these
choices are correct.
39) Potable water is
40) Indicator bacteria are
A) coliforms.
B) gram-negative rods.
C) evidence of fecal contamination.
D) used in water
quality tests.
E) All of these
choices are correct.
41) Analysis of a water sample by a series of presumptive,
confirmatory, and completed tests that help establish an
estimate of coliform numbers in the water is called
42) An example of a primary consumer would be a
Version 1 22

A) None
B) 5%
C) 10%
D) 50%
E) 90%
44) Which of the following cannot be photoautrophs?