Active transport occurs ________ the concentration gradient across a cell membrane.
A. against
B. towards
C. away from
D. in between
E. passively against
A. against
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A circulatory system that allows some mixing of
oxygenated and oxygen-poor blood is indicated by a. A. b. B. c. C. d. A and B. e. all of these.
The foramen magnum is a passageway for
a. nasal cavities. b. eye sockets. c. spinal cord. d. Haversian (central) canals. e. synovial fluid.
Fossils would include
a. skeletons. b. shells. c. seeds. d. tracks. e. all of these.
Select the TRUE statement(s) about respiratory diseases. (Select all that apply.)
a. Severe mountain sickness can cause pulmonary edema. b. Smoking often damages alveolar walls, making oxygen delivery difficult or impossible. c. At high altitudes, humans adapt by enlarging the lungs and increasing the number of alveoli. d. Severe mountain sickness causes pulmonary edema due to high pressures in the pulmonary artery, induced by hypoxia and the sympathetic nervous system.