Contact immunity within a population can be produced by ________ vaccines.
A. attenuated
B. DNA
C. inactivated
D. subunit
E. toxoid
Answer: A
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A buffer system
a. makes new hydrogen ions. b. eliminates hydrogen ions already present. c. binds carbon ions. d. releases hydrogen ions. e. produce excess acid.
When the body has excess sodium, which of the following does NOT happen?
a. more sodium is excreted b. more sodium is reabsorbed c. edema (swelling) occurs d. blood pressure rises e. aldosterone secretion is inhibited
What organism do coral animals harbor inside their bodies to provide them with nutrition?
A) bacteria B) dinoflagellates C) photosynthetic algae D) hydras
Prokaryotes and eukaryotes are primarily distinguished by the absence or presence of internal membrane-enclosed organelles. Are prokaryotic cells at an evolutionary disadvantage because they lack organelles?
a. Yes; without organelles, prokaryotic cells cannot photosynthesize or respire. b. Yes; without organelles, prokaryotes are unable to bring together the reactants needed for biological reactions. c. No; although prokaryotic cells are comparatively less efficient than eukaryotic cells, they are still able to carry out the processes necessary for survival and reproduction. d. No; eukaryotic organelles are expelled each time the cell divides.