31. A synergistic effect is observed when

A. one organism removes an inhibitory substance for another
B. one organism produces a growth factor utilized by another
C. microbial alteration of pH, a_w, Eh favors the growth of another
D. all of the above

32. Generation time is

A. time required for the population to double
B. time required for the initial adjustment
C. obtained by expression t/n, where t = time interval, n = number of generation
D. both (a) and (c)

33. The term facultative anaerobe refers to an organism that

A. doesn’t use oxygen but tolerates it
B. is killed by oxygen
C. uses oxygen when present or grows without oxygen when absent
D. requires less oxygen than is present in air

34. The microorganisms that grow best in a low-oxygen environment is called a (n)

A. aerobe
B. anaerobe
C. facultative
D. microaerophile

35. Pseudomonas pseudoflava can grow as

A. chemo-lithotrophs
B. chemo-organotrophs
C. both (a) and (b)
D. none of these