A gram-negative bacillus that is hydrogen sulfide (H2S)-positive, citrate-positive, spot in-dole–negative, and associated with gastroenteritis in the United States is most likely:
a. K. pneumoniae.
b. P. vulgaris.
c. Salmonella enteritidis.
d. S. sonnei.
C
H2S-positive is the clue that gives away Salmonella spp. in this case. Although P. vulgaris is the only other organism that is H2S-positive, it is spot indole–positive, not negative.
You might also like to view...
Ecologists are concerned about amphibian populations because
A. their loss would be an aesthetic loss to the planet. B. of the possibility of numerous medicinal uses. C. they are keystone species in many areas—their loss will cause other populations to crash. D. amphibians are very sensitive to environmental change—they may be indicating serious problems. E. they are increasing to the point of competing with indigenous species.
Disturbances:
A. involve interactions such as competition and predation. B. affect populations differently according to their density. C. usually only affect one particular species in a community. D. are extremely rare. E. can influence the diversity of a species in a community.
Which of the following is eliminated in rapidly dividing embryonic cells that get smaller with each cell division?
A) G1 phase B) S phase C) G2 phase D) M-phase chromosome separation E) M-phase cytokinesis
"Cole" refers to any of various plants belonging to the Cruciferae or mustard family, which include broccoli, cabbage, collard greens, and other familiar vegetables
The controlled breeding of cole crops to produce certain physical traits in those organisms is called A) artificial selection. B) natural selection. C) agricultural selection. D) physical selection.