Which valve is responsible for preventing the backflow of blood into the right ventricle?
A. tricuspid
B. bicuspid
C. pulmonary semilunar
D. mitral
E. aortic valve
Answer: C
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Which portion of the brain is not protected by the blood-brain barrier?
a. pons b. cerebellum c. thalamus d. cerebrum e. hypothalamus
What initiates the sodium-potassium pump?
A. Two potassium ions are transported into the cell. B. ATP binds to the protein which becomes phosphorylated (ADP is released). C. Three sodium ions are translocated out of the cell. D. Three sodium ions bind to the cytoplasmic side of the protein. E. Phosphorylated pump has low affinity for sodium allowing sodium to leave and potassium to bind.
During photosynthesis, when is CO2 utilized?
A) During the light reactions only B) During the Calvin cycle only C) During both the light reactions and the Calvin cycle D) During neither the light reactions nor the Calvin cycle
In 1859, Charles Darwin wrote, "The affinities of all the beings of the same class have sometimes been represented by a great tree... As buds give rise by growth to fresh buds, and these if vigorous, branch out and overtop on all sides many a feebler branch, so by generation I believe it has been with the great Tree of Life, which fills with its dead and broken branches the crust of the earth, and covers the surface with its ever branching and beautiful ramifications." At the base of the evolutionary tree of all life is ___________.
A. the first tetrapod B. an amniote C. an organism that is a common ancestor to all living organisms. D. a fork that represents the split between plants and animals.